text:
High School Physics/Si units

The SI Unit System
If physical quantities are measured using different systems of units, the magnitudes would be different. It would become inconvenient and difficult to compare results. It has been also observed that the units of some physical quantities related to heat, light, current electricity, etc. have complicated relations with some basic physical quantities and can be expressed using them. The resulting units are therefore impractical. Taking these problems into account, the International Bureau of Weights and Measures recommended a new system of units, International System of Units (SI). SI units provide and international standard of measurement and are used widely.

So, there are seven base SI units.

Base units

 * Meters (Distance)
 * Describes the space between two locations. Think of the length of a highway or the distance between two cities. The definition of the meter has changed in the last few years. The meter was originally defined as one ten millionth of the distance from one of the Earth's poles to the equator. The meter is now defined as the length of the path travelled by light in vacuum during a time interval of $$1/299,792,458$$ of a second.

 * Kilograms (Mass)
 * Describes how much matter an object has. Think of the difference between a small female gymnast and large male football player. The two athletes' bodies move differently because of their difference in mass. The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.

 * Seconds (Time)
 * Describes the passage of time or aging of the universe.The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom.

 * Kelvin (Thermodynamic temperature)
 * The kelvin is the fraction $$1/273.16$$ of the thermodynamic temperature of the triple point of water.

 * Mole (Amount of substance mole)
 * 1. The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12; its symbol is "mol."
 * 2. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.

 * Ampere (Electric current)
 * The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 2 newton per meter of length.

 * Candela (Luminous intensity)
 * The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.

Derived units

 * Force $$\rm N$$
 * The Newton is a product of mass with acceleration, representing a force.
 * $$1.0\,\rm N=0.24\,\rm lb$$ of force, defining lbs using Earth's value of gravity

 * Velocity $$\frac{\rm m}{\rm s}$$
 * The motion of an object based on time, with a direction. Velocity is always specified with a direction, such as “12 miles per hour north”.
 * If the direction is not specified, it is called speed.

 * Acceleration $$\frac{\rm m}{\rm s^2}$$
 * The rate at which an object is changing velocity.

 * Momentum $$\rm kg\cdot\frac{\rm m}{\rm s}$$
 * The product of mass and speed. Note that heavy or fast objects have high momentums.

 * Energy $$\rm J$$
 * The Joule is a product on force and distance.

Conversions
Though best learned in chemistry, conversion are simply ways in which you can represent a relative quantity.

title: High School Physics/Si units


text:
Linux Guide/Desktop environments

Linux GUIs
Desktop environments and window managers are not the same. With X11, a desktop environment includes all the software needed for a desktop, including a window manager, but a window manager only manages the windows and does not include any other software. Sometimes window managers provide extra features, such as a pager. Under Wayland, this is a little different: all of these are called compositors, and are actually a display server implementation, like X server itself. They range in complexity, and will often describe themselves as comparable to window managers or desktop environments.

Desktop environments

 * GNOME|thumb
 * GNOME (pronounced /ɡəˈnoʊm/) is a desktop environment composed entirely of free and open source software. It is an international project that includes creating software development frameworks, selecting application software for the desktop, and working on the programs which manage application launching, file handling, and window and task management.
 * GNOME is part of the GNU Project and can be used with various Unix-like operating systems, most notably those built on top of the Linux kernel and the GNU userland, and as part of the Java Desktop System in Solaris.
 * GNOME is also a Wayland compositor.
 * See Using GNOME

 * Plasma 5KDE Plasma 5.png
 * Plasma is a free software project by the KDE (pronounced /ˌkeɪdiːˈiː/) community, and is a cross-platform desktop environment designed to run on Linux, Windows and Mac OS X systems. The goal of the project is to provide basic desktop functions and applications for daily needs as well as tools and documentation for developers to write stand-alone applications for the system. In this regard, the KDE project serves as an umbrella project for many standalone applications and smaller projects that are based on KDE technology. KDE software is based on the Qt toolkit. The original GPL version of this toolkit only existed for the X11 platform, but with the release of Qt 4, GPL versions are available for all platforms. This allows KDE software based on Qt 4 to also be distributed to Microsoft Windows and Mac OS X. Currently, Plasma and all of its included software use Qt 5.
 * Plasma is also a Wayland compositor.
 * See Using KDE

 * XFCE|thumb
 * Xfce (pronounced as four individual letters) is a free software desktop environment for Unix and other Unix-like platforms, such as Linux, Solaris and BSD. It aims to be fast and lightweight, while still being visually appealing and easy to use.
 * The current version is . It consists of separately packaged components that together provide the full functionality of the desktop environment, but which can be selected in subsets to create the user's preferred personal working environment. Xfce is mainly used for its ability to run a modern desktop environment on relatively modest hardware.
 * It is based on the GTK+ 3 toolkit (the same as GNOME). It uses the Xfwm window manager. Its configuration is entirely mouse-driven, and the configuration files are hidden from the casual user.

LXDE is a lightweight X11 desktop environment. However, it is slated to be replaced by LXQt.
 * LXDELXDE_desktop_full.png

Note: Both GNOME and KDE use comparatively higher system resources than XFCE and standalone window managers. So if you are on an old PC you should seriously consider XFCE or a window manager over the heavyweights. Same apply if you find KDE or GNOME somehow slow on your high end workstation. IceWM, though minimalist, is fast, reliable, themable, and less resource intensive than the others.

Window managers

 * CompizXgl window switching.pngFedora-Core-6-AIGLX.png
 * Compiz is one of the first compositing window managers for the X Window System that uses 3D graphics hardware to create fast compositing desktop effects for window management. The effects, such as a minimization effect and a cube workspace are implemented as loadable plugins. Because it conforms to the Inter-Client Communication Conventions Manual standard, Compiz can substitute for the default Metacity in GNOME or KWin in KDE.
 * Compiz plugins include the famous cube effect (example to the right), Alt-Tab application-switching with live previews or icons, and a feature similar to Exposé.

 * Enlightenment
 * Enlightenment, also known simply as E, is a stacking window manager for the X Window System which can be used alone or in conjunction with a desktop environment such as GNOME or KDE. Enlightenment is often used as a substitute for a full desktop environment.
 * One can compile Enlightenment to enable experimental Wayland support.

 * FLUXBOXAdesklets.jpgFluxbox.png
 * Fluxbox is a stacking window manager for the X Window System with the aim to be lightweight. Its user interface has only a taskbar, a pop-up menu accessible by right-clicking on the desktop, and minimal support for graphical icons. All basic configurations are controlled by text files, including the construction of menus and the mapping of keybindings. Fluxbox has high compliance to the Extended Window Manager Hints specification.
 * Fluxbox can show some eye candy: colors, gradients, borders, and several other basic appearance attributes can be specified. Recent versions support rounded corners and graphical elements.
 * Because of its small memory footprint and quick loading time, Fluxbox is popular in many Live CDs such as Knoppix STD and GParted.

 * FVWMFvwm wiki screen.png
 * The F Virtual Window Manager is a virtual window manager for the X Window system. Originally a twm derivative, FVWM has evolved into a powerful and highly configurable environment for UNIX systems.

 * IceWMIcewm1220.png
 * IceWM is a stacking window manager for the X Window System graphical infrastructure. It is relatively lightweight in terms of memory and CPU usage, and comes with themes that allow it to imitate the GUI of Windows 95, OS/2, Motif, and other graphical user interfaces. IceWM is meant to excel in look and feel while being lightweight and customizable.
 * IceWM can be configured from plain text files stored in a user's home directory, making it easy to customize and copy settings. IceWM has an optional, built-in taskbar with menu, tasks display, network and CPU meters, mail check and configurable clock. Official support for GNOME and KDE menus was previously available as a separate package. In recent IceWM versions, support for them is embedded. External graphical programs for editing configuration and menu exist.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Linux Guide/Desktop environments


text:
Linux Guide/Distributions

A distribution is a type of Linux. Linux comes in a large number of distributions, some of which are designed for everyday use, and others designed with a specific task or device in mind. We'll discuss some of those differences below.

Most Linux distributions have a special type of CD, called a live CD. If you insert this CD and then restart your computer, the live CD will run Linux on the computer while avoiding changing anything on your computer as much as possible. For example it won't normally install any files on your PC, but run only from the CD. You can give the operating system a try to see if you like it without the risk of installing anything on your hard drive. You should remember that linux typically runs very fast - if the system seems slow, it is because it is running off your CD drive, not your hard drive.

Choosing A Distro
There are dozens of different Linux distributions. Here are some ways to help you narrow down the options to a short list.

 * How do you intend to use the system?
 * Desktop or server? This distinction is probably the most important. Distributions for the desktop will have a graphical user interface, while server distributions won't.

 * Specific hardware requirements
 * Try out a few LiveCDs of different distributions. Does it recognize and work properly with your hardware?
 * If you intend to install Linux on a low-end specification computer, or you have other peculiar hardware compatibility problems or requirements, your choice might be influenced by this need. Most linux distributions should run fine on all but the lowest end of the spectrum.

 * Application support
 * Which applications or desktop environment are important to you?
 * Does a given distribution install those programs by default or is it easy to install and integrate them with the rest or your system?
 * Does the distribution have a good package management system, and suitable software repositories?

 * Support
 * What options will be available for getting support? Is commercial (paid) support available? Is there free community support? If the distribution has a small user base, you will have a harder time getting distribution-specific support, as compared to a more widely-used distribution.

 * Desktop environment
 * For desktop systems, you'll need to feel at home. Check out ../Desktop environments for information on some common ones. GNOME and KDE are the two most popular.

Try a distro chooser, like http://www.zegeniestudios.net/ldc/. Often several different distributions will meet all your requirements. Your final choice from the short list may be based on whim or personal taste.

Selected distributions

 * Main page: ../Distros in detail

 * Arch
 * A minimalistic and lightweight distribution that caters to the experienced Linux user. User-contributed build scripts for many programs are available in the Arch User Repository.

 * Debian
 * Contains a lot of packages.
 * Comparatively easy to use and update.
 * Very stable; expect a longer wait between software updates.

 * Fedora
 * Free version of Red Hat Linux.

 * Gentoo
 * Offers four levels of installation, very time consuming, but easy to upgrade.
 * Used mainly by advanced users. All packages are compiled from source, which makes it easy to exclude unneeded parts of software, or optimize programs for the user's system. This includes the Linux kernel.

 * Linux From Scratch
 * This page details how to build a Linux system without relying on any particular distribution. For experts only.

 * Linux Mint
 * Makes Ubuntu easier with improved hardware detection, scripts, and multimedia integration.

 * Mageia Linux
 * A distribution based on the now-discontinued Mandriva Linux, with easy configuration utilities and many useful applications.

 * Manjaro
 * Based on Arch, but a lot easier to install and use.

 * openSUSE
 * Distribution designed mostly for business, but very user friendly and easy to pick up and use.

 * PCLinuxOS
 * Very popular for beginners.

 * Red Hat
 * Commercial distribution (but see centOS) designed mostly for business, yet also usable for individuals.
 * The free version is Fedora (above)

 * Sabayon
 * Gentoo Linux-based distribution that focuses on newest technologies.

 * Slackware Linux
 * One of the first Linux distributions.
 * Easy installation, but a bit of knowledge would be useful. Users are encouraged to install all of the available software along with the system. This does not slow down the system, as none of them are enabled by default. This cuts down on package management significantly.

 * Ubuntu
 * The most successful and popular desktop distro based on Debian.
 * Uses the Gnome user interface and has frequent updates.
 * Very easy to use and install.
 * Ubuntu Linux has different variations:
 * Kubuntu: Uses KDE instead of Gnome. Also see KubuntuGuide.
 * Xubuntu: A light-weight version of Ubuntu that uses Xfce instead of Unity. This version is useful for less powerful PCs and for people who want a simple interface.
 * Lubuntu: A very light-weight but still full-featured version that uses LXDE instead of Gnome. This version is useful for legacy PCs and for people that want to get the most out of their hardware.  Lighter than even Xubuntu.
 * Edubuntu: Distribution designed for educational purposes.
 * Studio: Distribution designed for multimedia production.
 * Linux Mint (above) is a remastered version of Ubuntu

title: Linux Guide/Distributions


text:
Linux Guide/Introduction

Introduction
Welcome to the world of free and open source software!

Welcome to Linux! GNU/Linux is descended from the UNIX operating system, but it is open source software, which means that you can view its source code and change it to suit your needs. Of course, since this book is geared to those new to Linux, we stay away from very technical issues that are more suited to Linux veterans. This book is going to try to be geared toward the person who has heard about Linux and might be considering trying it out or perhaps the person who has already "taken the plunge" and is looking for more information or wondering where to start now that they have Linux installed. But first, a little history lesson.

The name "Linux" technically refers to an operating system "kernel", a single but key component of a complete operating system. In everyday use, the term "Linux" is frequently used to refer to a complete operating system which consists of the kernel and some of the thousands of other programs required to make an operating system useful. Much of the important system software that is typically installed on a Linux system comes from The GNU Project, a project to build an operating system made entirely of free software.

The first Linux kernel was created by Linus Torvalds. It was first released on 5 Oct 1991. It was started as an x86-only, single-processor operating system, but grew to become one of the most ported pieces of software. Other parts of a complete GNU/Linux system come from other projects such as the GNU project, and are integrated into a complete GNU/Linux OS by your supplier. Usually your supplier will assign their own version number to the integrated whole.

The GNU Project is overseen by the Free Software Foundation, founded by Richard Stallman, who believes that the people should use the term "GNU/Linux" to refer to such an operating system, because so many of the required programs were in fact, written as part of the GNU Project.

title: Linux Guide/Introduction


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High School Physics/Physics experiments

Force
Rubber bands, known weights

Electricity
Wheatstone bridge, resistors, various materials Rubber, metal, steel wool Electrochemical Cells High voltage, low capacitance "human" circuits. Parallel vs. series.

Heat
Simple Solar Cookers Temperature equilibrium Energy of common foods

Multi-subject projects Making a better mousetrap...car that is. Floating boats: making boats out of balsa and seeing who can get trough the 20 meter float. The green cannon: Using renewable energy to accelerate a tennis ball

Sound
Computer speakers Representation of waves Annoying music, characteristic waves.

title: High School Physics/Physics experiments


text:
Linux Guide/Runlevels

Starting Linux (Booting)
When a computer is turned on, it normally begins the process of "booting" by reading software from the system's hard disk (or other non-volatile storage medium), and loading it into memory and then executing it. In this process the kernel is loaded and then various other system programs may be loaded.

A Linux system can be configured to boot up to one of several available "run levels":

0    Halt the system. 1    Single-user mode (for special administration). 2    Single User Mode with Networking 3    Multi-User Mode - boot up in text mode 4    Not yet Defined 5    Multi-User Mode - boot up in X Windows 6    Reboot.

Debian
The following quote from The Debian GNU/Linux FAQ explains how to add a custom procedure to a Debian or Debian based system boot:

''Suppose a system needs to execute script foo on start-up, or on entry to a particular (System V) runlevel. Then the system administrator should:

 * Enter the script foo into the directory /etc/init.d/.
 * Run the Debian command update-rc.d with appropriate arguments, to set up links between the (command-line-specified) directories rc?.d and /etc/init.d/foo. Here, '?' is a number from 0 through 6 and corresponds to each of the System V runlevels.
 * Reboot the system.

''The command update-rc.d will set up links between files in the directories rc?.d and the script in /etc/init.d/. Each link will begin with a 'S' or a 'K', followed by a number, followed by the name of the script. Scripts beginning with 'S' in /etc/rcN.d/ are executed when runlevel N is entered. Scripts beginning with a 'K' are executed when leaving runlevel N.''

title: Linux Guide/Runlevels


text:
A-level Mathematics/OCR/FP3

This is the Further Pure Mathematics 3 module of the A-level Mathematics book. This module assumes that you are familiar with the ../C1/, ../C2/, ../C3/, ../C4/ and ../FP1/ modules. Please post all questions to A-level Mathematics/Discussion.

Contents

 * 1) /More About Differential Equations/
 * 2) /More About Vectors/
 * 3) /Hyperbolic Functions/
 * 4) /Complex Numbers/
 * 5) /Groups/

Formulae
By the end of this module you will be expected to have learnt the following formulae:

Differential Equations

 * An integrating factor of $$\frac{dy}{dx} + P(x)y = Q(x) $$ is $$ e^{\int P(x)\, dx}$$

Vectors

 * The vector equation of a plane through point $$\mathbf{a}$$ with normal vector $$\mathbf{n}$$ is $$(\mathbf{r}-\mathbf{a})\cdot\mathbf{n} = 0 $$

Complex Numbers
If $$ z = e^{i\theta}$$ then:
 * $$ \cos \theta = \frac{1}{2}\left(z+\frac{1}{z}\right) $$
 * $$ \sin \theta = \frac{1}{2i}\left(z-\frac{1}{z}\right) $$

title: A-level Mathematics/OCR/FP3


text:
A-level Mathematics/OCR/S1/Representation of data

Representation of data
Data that is presented in a systematic manner is much easier to understand. Consequently the next step after data collection is to lay the information out in an orderly way - usually as a table.

A well constructed table must have a) A clear, comprehensive, explanatory title b) Be systematically formated c) Identify the source of the data d) All units of measurment must be clearly stated (sometimes in the headings of the columns or rows) e) The headings to all columns and rows must be unambiguous - if it would be too long, then use a short title PLUS a footnote.

Systematic formating is the hard bit. Here you must ask yourself what is the purpose of the table: a) To present the data collected in an orderly manner b) To show distinct patterns in the data c) To summarise the data In most cases, good layout is obtained by first asking what data must be presented adjacent to each other and then asking supplementary questions such as should totals be shown, should percentages or other derived statistics be shown, or would they just clutter up the table.

NEEDS SOME EXAMPLES HERE, probably as graphics to avoid the limitations of web page rendering on different browsers ***

Graphs and Diagrams
SYLABUS EXTRACT:

pie charts, bar charts frequency polygons, construct and interpret stem-and-leaf diagrams (including ordered and back-to-back stem-and-leaf diagrams), box-and-whisker plots, histograms and cumulative frequency graphs - To be written


text:
A-level Mathematics/OCR/S1/Bivariate Data

Bivariate data
SYLABUS EXTRACT:

(a) calculate, both from simple raw data and from summarised data, the product moment correlation coefficient for a set of bivariate data; (b) understand the basis of Spearman’s coefficient of rank correlation, and calculate its value (questions set will not involve tied ranks); (c) interpret the value of a product moment correlation coefficient or of Spearman’s rank correlation coefficient in relation to the appearance of a scatter diagram, with particular reference to values close to 1, − 0,1; (d) understand that the value of a correlation coefficient is unaffected by linear transformations (coding) of the variables; (e) understand the difference between an independent (or controlled) variable and a dependent variable; (f) understand the concepts of least squares and regression lines in the context of a scatter diagram; (g) calculate, both from simple raw data and from summarised data, the equation of a regression line, understand the distinction between the regression line of y on x and that of x on y, and use the fact that both regression lines pass through the mean centre (x, y); (h) select and use, in the context of a problem, the appropriate regression line to estimate a value, and be able to interpret in context the uncertainties of such estimations.


text:
A-level Mathematics/OCR/S1/Probability

New S1 syllabus does not include lot of these topics

Combinations and Permutations
Permutation - The total number of ways of arranging r objects from n, where order is important, e.g. choosing a school football team and positions, where anyone can play any position

Combination - The total number of ways of choosing r objects from n, where order is not important, e.g. choosing three cards from a deck, so that you gain a 2, a 3 and a 4 in no particular order

Combinations - Use the button marked nCr on a calculator, or the formula $$\frac{n!}{(n-r)!r!}$$

Permutations - Use the button marked nPr on a calculator, or the formula $$\frac{n!}{(n-r)!}$$

Probability
Syllabus Extract:

(a) understand the terms permutation and combination; (b) solve problems about selections, e.g. finding the number of ways in which a team of 3 men and 2 women can be selected from a group of 6 men and 5 women; (c) solve problems about arrangements of objects in a line, including those involving (i) repetition (e.g. the number of ways of arranging the letters of the word ‘NEEDLESS’), (ii) restriction (e.g. the number of ways several people can stand in a line if 2 particular people must — or must not — stand next to each other); (d) evaluate probabilities in simple cases by means of enumeration of elementary events (e.g. for the total score when two fair dice are thrown) or by calculation using permutations and combinations; (e) use addition and multiplication of probabilities, as appropriate, in simple cases; (f) understand informally the meaning of exclusive and independent events, and calculate and use conditional probabilities in simple cases, e.g. situations that can be represented by means of a tree diagram.

title: A-level Mathematics/OCR/S1/Probability


text:
A-level Mathematics/OCR/S1/Discrete Random Variables

Derived statistics
SYLABUS EXTRACT:

Understand, use and interpret different measures of central tendency (mean, median, mode) and variation (range, interquartile range, standard deviation), e.g. in comparing and contrasting sets of data; Calculation of the mean and standard deviation of a set of data (including grouped data) either from the data itself or from given n totals such as Σx and Σx2, or Σ(x−a) and Σ(x−a)2.

Discrete random variables
SYLABUS EXTRACT:

(a) construct a probability distribution table relating to a given situation involving a discrete random variable X, and calculate the expectation, variance and standard deviation of X (the notations E(X ) for expectation (also referred to as expected value or mean) and Var(X ) for variance, are included); (b) use formulae for probabilities for the binomial and geometric distributions, and model given situations by one of these, as appropriate (the notations B(n, p) and Geo( p) are included); (c) use tables of cumulative binomial probabilities (or equivalent calculator functions); (d) use formulae for the expectation and variance of the binomial distribution, and for the expectation of the geometric distribution.


text:
A-level Mathematics/OCR/S2

Please post all questions to A-level Mathematics/Discussion.

Contents

 * 1) /Continuous Random Variables/
 * 2) /Normal Distribution/
 * 3) Poisson Distribution
 * 4) /Sampling and Hypothesis Tests/

title: A-level Mathematics/OCR/S2


text:
A-level Mathematics/OCR/S3

Please post all questions to A-level Mathematics/Discussion.

Contents

 * 1) /More about Continuous Random Variables/
 * 2) /Linear Combinations of Random Variables/
 * 3) /Confidence Intervals and t Distribution/
 * 4) /Difference of Population Means and Proportions/
 * 5) /χ² tests/

title: A-level Mathematics/OCR/S3


text:
A-level Mathematics/OCR/S4

Please post all questions to A-level Mathematics/Discussion.

Contents

 * 1) /Advanced Probability/
 * 2) /Non-parametric Tests/
 * 3) /Probability Functions/
 * 4) /Moment Generating Functions/
 * 5) /Estimators/
 * 6) /Discrete Bivariate Distributions/

title: A-level Mathematics/OCR/S4


text:
Bicycles/Equipment and Accessories/Lights

Lights are an essential cycling accessory and any cyclist that intends to ride in dim lighting conditions, or poor weather such as fog or rain should not consider riding without lights.

Why use lights?
Although bikes sold for use on the roads are required to be supplied with reflectors, these really should not be relied on to keep you visible on the roads. Cyclists should be responsible for their own safety and acknowledge that not only are proper lights a common courtesy to other road users, they are one of the ways to promote your safety on the roads. Darkness and bad weather can make cyclists almost invisible to other road users. A light may be the only thing that makes a driver or pedestrian realize that the faint shadow up ahead is actually a cyclist.

Types of Lighting
There is a wide selection of bicycle lights available, all with their own characteristics. It is definitely worth discussing your needs and cycling habits with the staff in the store you intend to buy your lights from.

There are generally three types of lighting used for bicycles, based around either Light Emitting Diodes (LEDs), Halogen filament bulbs or High-Intensity Discharge (HID) bulbs. It is very rare to see lights based around other light sources, so unless they are expressly recommended by an expert they should be treated with caution when buying. Bicycle lights can also be powered by different means. The most common are ordinary batteries, rechargeable batteries, "bottle" dynamos and Hub dynamos.

LED lighting systems
LED lights are very popular amongst cyclists and have a number of excellent characteristics. They are lightweight, relatively cheap, bright, compact and reliable. They require very little maintenance- LEDs have a very long lifespan and don't need to be replaced like bulbs. LEDs are generally battery powered and give excellent battery life. Many LED lighting systems are also demountable; you can detach the lights and take them with you if you are going to leave your bike locked up in public.

LED lights often come with the option of a variety of flashing modes, as well as a steady beam. While you are required by law to have lights attached to the frame that emit a steady beam, many cyclists also attach additional lights to their bike or clothing that are set to flash. Flashing lights tend to attract the attention of drivers and increase battery life although with LED there is little need to increase the battery life, especially if using rechargable batteries, and flashing lights can be distracting to other road users or cause you to be in more danger because it is more difficult to judge the distance of a flashing light.

One issue with LEDs is that they emit quite a narrow beam that appears weaker the further you move from the optimum viewing angle. All LED lights should have a light diffuser which will increase their effectiveness.

In 2014, modern high power white LEDs can be very bright, currently up to slightly over 1000 lumens from a single emitter and can completely replace older lighting systems under all conditions.

Halogen lighting systems
Most cyclists find that LEDs do not provide a powerful enough beam to illuminate the road. This means that while they work very well as a tail light in all conditions and as a headlight in areas with street lighting they will not provide illumination of the way ahead like a car's headlights might. Cyclists that need to cycle down unlit roads often choose a Halogen light for their headlight. Halogen lights give a very bright beam for relatively low power consumption, although they are more power hungry than LED systems. They tend to be available with more power source options than LED lights, such as rechargeable batteries and dynamos. Because they use more batteries and produce more heat than LEDs, halogen lights also tend to be very slightly bigger and heavier than LEDs, the trade off being their superior performance for specialist use.

Power Sources
Bicycle lights are normally powered by either batteries or dynamos. The Key difference between batteries and dynamos is that, by using a dynamo you generate your own electricity to power the lights on your bike and by using batteries you get power from a disposable (and environmentally harmful) source. Both the lights and the generators for Dynamo systems are initially more expensive than battery powered lights, however this can be offset over the lifespan of the product by the fact that you are not paying to recharge or replace batteries. While most battery powered lights attach to the bike by a simple clip mechanism, meaning they can be removed to prevent theft, most dynamo lights have to remain clipped to the frame due to the wiring that connects them to the Dynamo.

Battery power
LED systems tend to run off battery power, as it provides a steady, constant, compact and lightweight source of power that suits the characteristics of LED systems. LEDs don't use battery power very quickly and are a very economical form of bicycle lighting. You can use your own rechargeable batteries but they tend not to come as standard

Increasing your visibility
Wear light coloured clothing and reflective or illuminated materials. Make sure that the reflectors fitted to your bicycle are still attached. In the UK it is a legal requirement to have pedal reflectors and a rear reflector in addition to a white front light and a red rear light. Many cyclists are struck by vehicles emerging from side streets so consider fitting additional reflectors that work from the sides. Reflectors are available that fit to the wheels or onto spokes. Try to use lights that emit some light sideways as well as just forwards and backwards. Use your lights in low visibility conditions, for example if it is raining heavily or foggy, or if you are cycling when the sun is low in the sky and could dazzle other road users. Make sure that your lights are clean and that the batteries are in good condition. If you do not have suitable lighting or are caught out by nightfall, walk your bike instead of riding home you are better of late than _the_ late.

Tips
Always check that the lights you buy are weatherproof. You will need them in the rain!

Links with more information
http://en.wikipedia.org/wiki/Bicycle_lighting Wikipedia entry on bicycle lighting http://www.runmuki.com/commute/ a guide to bicycle communing http://www.lcc.org.uk/ the London Cycling Campaign website


text:
User talk:Tthorp

Excel screenshots
Please mark screenshots from Microsoft Excel as software-screenshot, not GFDL-self. Can you changed your previous images? --Derbeth talk 13:35, 16 December 2005 (UTC)

title: User talk:Tthorp


text:
User talk:Sithanthaseelan

Image:2004-xii-accountancy-67-2-1.pdf
"Free screenshot" is not applicable for a document - I would reccomend GFDL-self (if you are the author). --Derbeth talk 13:36, 16 December 2005 (UTC)

title: User talk:Sithanthaseelan


text:
User talk:210.55.230.19

Please stop adding nonsense to Wikibooks. It is considered vandalism. If you would like to experiment, use the sandbox. Thank you.

title: User talk:210.55.230.19


text:
User talk:216.37.223.82

Welcome!
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title: User talk:216.37.223.82


text:
User talk:Kundash~enwikibooks

Come introduce yourself at the new users page. If you have any questions, you can ask there or contact me personally.

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Kundash. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Kundash~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

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Sorry for the inconvenience.

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Renamed
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title: User talk:Kundash~enwikibooks


text:
User talk:Aleksev

Anti-Vandalism Patrol
Thank you for your work on the last Anti-Vandalism patrol. Any help to revert damage is always appreciated, particularly when it can be so offensive. --Rob Horning 14:01, 16 December 2005 (UTC)

 * Yep, thanks for the reversion of my talk page. Cheers. -- LV (Dark Mark) 18:35, 17 December 2005 (UTC)

A-Level Math C1
Both these websites state some intergration is on the C1 exam. http://www.mathsrevision.net/alevel/pure/ http://www.mathsnet.net/asa2/2004/c1.html Is there something that I'm missing? Did the exam change? Keytotime 19:47, 4 May 2006 (UTC)

Understood and will follow Keytotime 19:03, 5 May 2006 (UTC)

title: User talk:Aleksev


text:
User:Compatta

Current environmental science major at san diego state university, i have always loved the idea of doing physical experiments. Possibly, i want to become a physics teacher in the future that can make students realize that physics is relevant and that their are many opportunities in science that students can and should realize.

Noticing a trend that not as many students are pursuing sciences and engineering in general, i want to make them realize that regardless of what they may become, science can and should be applied to life in general.

e-mail: compatta(at)yahoo.com

My interests include:

 * 1) -physics
 * 2) -Cognitive learning models of physics (educational technology)
 * 3) -Integrating fun things with the ever complext curriculum in schools.
 * 4) -the general "tricks" that students can use to learn algebra and math in general easier to understand. Citing methods from around the world to figure out math (such as the mehtod to multiply extremely large numbers). Make complext areas of calculus that typically have the "academic brow" which tends to make cocnepts more complex than they should be.
 * 5) -Making texts in general more interesting for students. Not merely the study as my english teacher always said, "the study of dead white men's work."

My heroes include:
 * 1) -Hewitt, the person who conveyed that complex ideas can be represented in simple explanations and diagrams.
 * 2) -stallman, open source father.
 * 3) writer of "algebra for gansters"

title: User:Compatta


text:
Talk:Learn to Play Drums/Drum Tabs

You can link Tabs:drums or Tablature here. --Derbeth talk 14:10, 16 December 2005 (UTC)

Content
Is it worth having some pictures/videos of how to grip sticks/beat the drum, etc? It always helps me to see it being done. What's your thought? I could do some basic picture taking/recording and then upload that. Kayvan.walker 16:04, 6 August 2007 (UTC)

This is cool, I'll try to add to this page too, I think there should also be a section on playing different styles [Gio] 12/03/09

musical notation
Isn't that difficult, using something like musescore, and exporting to SVG. Can we do that too?

title: Talk:Learn to Play Drums/Drum Tabs


text:
User talk:InsayneWrapper~enwikibooks

Come introduce yourself at the new users page. If you have any questions, you can ask there or contact me personally.

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called InsayneWrapper. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name InsayneWrapper~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

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Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:14, 17 March 2015 (UTC)

Renamed
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title: User talk:InsayneWrapper~enwikibooks


text:
Rueda de Casino/El Dedo

From Guapea, instead of pushing, the leader changes to a right-to-right hold, and turns the follower to her right, then an Enchufa, still right-to-right.

He then turns himself to the left, turning his back on the follower, changing hands behind his back, so that he has left-to-right. He then does an Enchufa and Dile Que No.

Throughout the first two turns, the leader is moving clockwise around the follower.

Hand Signal: Raise the little finger of the right hand.

There are some variations:

 * Some leaders will keep right-to-right throughout, taking their right arm above their head.
 * Some leaders will reach to the middle with their right hand, after changing to left-to-right, and all push away from each other in the middle.

title: Rueda de Casino/El Dedo


text:
Calculus/Print version

=Table of Contents=
 * Introduction

Appendix

 * Choosing delta

Acknowledgements and Further Reading
=Introduction =

=Precalculus=

 Algebra

 Functions

 Graphing linear functions

 Precalculus Cumulative Exercises

=Limits=

 An Introduction to Limits

 Finite Limits

 Infinite Limits

Infinity is not a number

 Continuity

 Formal Definition of the Limit

 Proofs of Some Basic Limit Rules

 Limits Cumulative Exercises

=Differentiation= =Basics of Differentiation=

 Differentiation Defined

 Product and Quotient Rules

 Derivatives of Trigonometric Functions

 Chain Rule

 Higher Order Derivatives

 Implicit Differentiation

 Derivatives of Exponential and Logarithm Functions

 Some Important Theorems

 Basics of Differentiation Cumulative Exercises

=Applications of Derivatives=

 L'Hôpital's Rule

 Extrema and Points of Inflection

 Newton's Method

 Related Rates

 Optimization

 Euler's Method

 Applications of Derivatives Cumulative Exercises

=Integration= =Basics of Integration=

 Definite Integral

 Fundamental Theorem of Calculus

 Indefinite Integral

 Improper integrals

=Integration Techniques=

 Infinite Sums

 Derivative Rules and the Substitution Rule

 Integration by Parts

 Trigonometric Substitutions

 Trigonometric Integrals

 Rational Functions by Partial Fractional Decomposition

 Tangent Half Angle Substitution

 Reduction Formula

 Irrational Functions

 Numerical Approximations

 Integration Exercises

=Applications of Integration= =Area=

=Volume=

=Volume of solids of revolution=

=Arc length=

=Surface area=

=Work=

=Centre of mass=

Exercises
See the exercises for Integration =Parametric Equations= =Introduction=

=Differentiation=

=Integration=

=Polar Equations= =Introduction

=Differentiation=

=Integration=

=Sequences and Series= =Sequences=

=Series=

=Series and Calculus= =Taylor Series=

=Power Series=

Exercises
=Vector Calculations= =Vectors=

=Lines and Planes in Space=

=Multivariable & Differential Calculus=

=Ordinary Differential Equations=

=Partial Differential Equations=

<noinclude>

Exercises
</noinclude> =Extensions= =Systems of Ordinary Differential Equations=

=Real numbers=

=Complex Numbers=

=Advanced Integration Techniques=

Integration by Complexifying
=Appendix=

Calculus/Choosing delta
=Exercise Solutions=

=Algebra Solutions=

=Precalculus Cumulative Exercise Set Solutions=

=Limit Solutions=

=Infinite Limits/Infinity is not a number Solutions=

=Limits Cumulative Exercise Set Solutions=

=Differentiation Solutions=

=Differentiation Defined Solutions=

=Chain Rule Solutions=

=Some Important Theorems Solutions=

=Basics of Differentiation Cumulative Exercise Set Solutions=

=L'Hôpital's Rule Solutions=

=Related Rates Solutions=

=Applications of Derivatives Cumulative Exercise Set Solutions=

Integration Solutions
=Indefinite Integral Solutions=

=Definite Integral Solutions=

=Integration Cumulative Exercise Set Solutions=

<noinclude>

Sequences and Series Solutions
</noinclude> <noinclude>

Multivariable and Differential Calculus Solutions
</noinclude> =References= =Table of Trigonometry=

=Summation notation=

=Tables of Integrals=

=Tables of Derivatives=

=Acknowledgements and Further Reading=

title: Calculus/Print version


text:
X86 Assembly/16, 32, and 64 Bits

When using x86 assembly, it is important to consider the differences between architectures that are 16, 32, and 64 bits. This page will talk about some of the basic differences between architectures with different bit widths.

16-bit
The registers found on the 8086 and all subsequent x86 processors are the following: AX, BX, CX, DX, SP, BP, SI, DI, CS, DS, SS, ES, IP and FLAGS. These are all 16 bits wide.

On DOS and up to 32-bit Windows, you can run a very handy program called "debug.exe" from a DOS shell, which is very useful for learning about 8086. If you are using DOSBox or FreeDOS, you can use "debug.exe" as provided by FreeDOS.

 * AX, BX, CX, DX: These general purpose registers can also be addressed as 8-bit registers. So AX = AH (high 8-bit) and AL (low 8-bit).

 * SI, DI: These registers are usually used as offsets into data space. By default, SI is offset from the DS data segment, DI is offset from the ES extra segment, but either or both of these can be overridden.

 * SP: This is the stack pointer, offset usually from the stack segment SS. Data is pushed onto the stack for temporary storage, and popped off the stack when it is needed again.

 * BP: The stack frame, usually treated as an offset from the stack segment SS. Parameters for subroutines are commonly pushed onto the stack when the subroutine is called, and BP is set to the value of SP when a subroutine starts. BP can then be used to find the parameters on the stack, no matter how much the stack is used in the meanwhile.

 * CS, DS, SS, ES: The segment pointers. These are the offset in memory of the current code segment, data segment, stack segment and extra segment respectively.

 * IP: The instruction pointer. Offset from the code segment CS, this points at the instruction currently being executed.

 * FLAGS (F): A number of single-bit flags that indicate (or sometimes set) the current status of the processor.

32-bit
With the chips beginning to support a 32-bit data bus, the registers were also widened to 32 bits. The names for the 32-bit registers are simply the 16-bit names with an 'E' prepended.

 * EAX, EBX, ECX, EDX, ESP, EBP, ESI, EDI : These are the 32-bit versions of the registers shown above.

 * EIP : The 32-bit version of IP. Always use this instead of IP on 32-bit systems.
 * EFLAGS : An expanded version of the 16-bit FLAGS register.

64-bit
The names of the 64-bit registers are the same of those of the 32-bit registers, except beginning with an 'R'.

R8–R15 can be accessed as 8-bit, 16-bit, or 32-bit registers. Using R8 as an example, the names corresponding to those widths are R8B, R8W, and R8D, respectively. 64-bit versions of x86 also allow the low byte of RSP, RBP, RSI, RDI to be accessed directly. For example, the low byte of RSP can be accessed using SPL. There is no way to directly access bits 8–15 of those registers, as AH allows for AX.
 * RAX, RBX, RCX, RDX, RSP, RBP, RSI, RDI : These are the 64-bit versions of the registers shown above.
 * RIP: This is the full 64-bit instruction pointer and should be used instead of EIP (which will be inaccurate if the address space is larger than 4 GiB, which may happen even with 4 GiB or less of RAM).
 * R8–15: These are new extra registers for 64-bit. They are counted as if the registers above are registers zero through seven, inclusively, rather than one through eight.

128-bit, 256-bit and 512-bit (SSE/AVX)
64-bit x86 includes SSE2 (an extension to 32-bit x86), which provides 128-bit registers for specific instructions. Most CPUs made since 2011 also have AVX, a further extension that lengthens these registers to 256 bits. Some also have AVX-512, which lengthens them to 512 bits and adds 16 more registers.

 * XMM0~7 : SSE2 and newer.
 * XMM8~15 : SSE3 and newer and AMD (but not Intel) SSE2.
 * YMM0~15 : AVX. Each YMM register includes the corresponding XMM register as its lower half.
 * ZMM0~15 : AVX-512F. Each ZMM register includes the corresponding YMM register as its lower half.
 * ZMM16~31 : AVX-512F. 512-bit registers that are not addressable in narrower modes unless AVX-512VL is implemented.
 * XMM16~31 : AVX-512VL. Each is the lower quarter of the corresponding ZMM register.
 * YMM16~31 : AVX-512VL. Each is the lower half of the corresponding ZMM register.

8086 and 80186
The original 8086 only had registers that were 16 bits in size, effectively allowing to store one value of the range [0 - (216 - 1)] (or simpler: it could address up to 65536 different bytes, or 64 kibibytes) - but the address bus (the connection to the memory controller, which receives addresses, then loads the content from the given address, and returns the data back on the data bus to the CPU) was 20 bits in size, effectively allowing to address up to 1 mebibyte of memory. That means that all registers by themselves were not large enough to make use of the entire width of the address bus, leaving 4 bits unused, scaling down the number of usable addresses by 16 (1024 KiB / 64 KiB = 16).

The problem was this: how can a 20-bit address space be referred to by the 16-bit registers? To solve this problem, the engineers of Intel came up with segment registers CS (Code Segment), DS (Data Segment), ES (Extra Segment), and SS (Stack Segment). To convert from 20-bit address, one would first divide it by 16 and place the quotient in the segment register and remainder in the offset register. This was represented as CS:IP (this means, CS is the segment and IP is the offset). Likewise, when an address is written SS:SP it means SS is the segment and SP is the offset.

This works also the reversed way. If one was, instead of convert from, to create a 20 bit address, it would be done by taking the 16-bit value of a segment register and put it on the address bus, but shifted 4 times to the left (thus effectively multiplying the register by 16), and then by adding the offset from another register untouched to the value on the bus, thus creating a full 20-bit address.

Example
If CS = 258C and IP = 001216, then CS:IP will point to a 20 bit address equivalent to "CS × 16 + IP" which will be

258C × 1016 + 001216 = 258C0 + 001216 = 258D2 (Remember: 16 decimal = 1016).

The 20-bit address is known as an absolute (or linear) address and the Segment:Offset representation (CS:IP) is known as a segmented address. This separation was necessary, as the register itself could not hold values that required more than 16 bits encoding. When programming in protected mode on a 32-bit or 64-bit processor, the registers are big enough to fill the address bus entirely, thus eliminating segmented addresses - only linear/logical addresses are generally used in this "flat addressing" mode, although the Segment:Offset architecture is still supported for backwards compatibility.

It is important to note that there is not a one-to-one mapping of physical addresses to segmented addresses; for any physical address, there is more than one possible segmented address. For example: consider the segmented representations B000:8000 and B200:6000. Evaluated, they both map to physical address B8000.

B000:8000 = B000 × 1016 + 800016 = B0000 + 800016 = B8000, and

B200:6000 = B200 × 1016 + 600016 = B2000 + 600016 = B8000.

However, using an appropriate mapping scheme avoids this problem: such a map applies a linear transformation to the physical addresses to create precisely one segmented address for each. To reverse the translation, the map [f(x)] is simply inverted.

For example, if the segment portion is equal to the physical address divided by 1016 and the offset is equal to the remainder, only one segmented address will be generated. (No offset will be greater than 0F16.) Physical address B8000 maps to (B8000 / 1016):(B8000 mod 1016) or B800:0. This segmented representation is given a special name: such addresses are said to be "normalized Addresses".

CS:IP (Code Segment: Instruction Pointer) represents the 20-bit address of the physical memory from where the next instruction for execution will be picked up. Likewise, SS:SP (Stack Segment: Stack Pointer) points to a 20-bit absolute address which will be treated as stack top (8086 uses this for pushing/popping values).

Protected Mode (80286+)
As ugly as this may seem, it was in fact a step towards the protected addressing scheme used in later chips. The 80286 had a protected mode of operation, in which all 24 of its address lines were available, allowing for addressing of up to 16 MiB of memory. In protected mode, the CS, DS, ES, and SS registers were not segments but selectors, pointing into a table that provided information about the blocks of physical memory that the program was then using. In this mode, the pointer value CS:IP = 0010:2400 is used as follows:

The CS value 001016 is an offset into the selector table, pointing at a specific selector. This selector would have a 24-bit value to indicate the start of a memory block, a 16-bit value to indicate how long the block is, and flags to specify whether the block can be written, whether it is currently physically in memory, and other information. Let's say that the memory block pointed to actually starts at the 24-bit address 16440016, the actual address referred to then is 16440016 + 240016 = 16680016. If the selector also includes information that the block is 240016 bytes long, the reference would be to the byte immediately following that block, which would cause an exception: the operating system should not allow a program to read memory that it does not own. And if the block is marked as read-only, which code segment memory should be so that programs don't overwrite themselves, an attempt to write to that address would similarly cause an exception.

With CS and IP being expanded to 32 bits in the 386, this scheme became unnecessary; with a selector pointing at physical address 0000000016, a 32-bit register could address up to 4 GiB of memory. However, selectors are still used to protect memory from rogue programs. If a program in Windows tries to read or write memory that it doesn't own, for instance, it will violate the rules set by the selectors, triggering an exception, and Windows will shut it down with the "General protection fault" message.

32-Bit Addressing
32-bit addresses can cover memory up to 4 GiB in size. This means that we don't need to use offset addresses in 32-bit processors. Instead, we use what is called the "Flat addressing" scheme, where the address in the register directly points to a physical memory location. The segment registers are used to define different segments, so that programs don't try to execute the stack section, and they don't try to perform stack operations on the data section accidentally.

The A20 Gate Saga
As was said earlier, the 8086 processor had 20 address lines (from A0 to A19), so the total memory addressable by it was 1 MiB (or 2 to the power 20). But since it had only 16 bit registers, they came up with Segment:Offset scheme or else using a single 16-bit register they couldn't have possibly accessed more than 64 KiB (or 2 to the power 16) of memory. So this made it possible for a program to access the whole of 1 MiB of memory.

But with this segmentation scheme also came a side effect. Not only could your code refer to the whole of 1 MiB with this scheme, but actually a little more than that. Let's see how ....

Let's keep in mind how we convert from a Segment:Offset representation to Linear 20 bit representation.

The conversion:

Segment:Offset = Segment × 16 + Offset.

Now to see the maximum amount of memory that can be addressed, let's fill in both Segment and Offset to their maximum values and then convert that value to its 20-bit absolute physical address.

So, max value for Segment = FFFF16, and max value for Offset = FFFF16.

Now, let's convert FFFF:FFFF into its 20-bit linear address, bearing in mind 1610 is represented as 10 in hexadecimal.

So we get, FFFF:FFFF -> FFFF × 1016 + FFFF = FFFF0 (1 MiB - 16 bytes) + FFFF (64 KiB) = FFFFF + FFF0 = 1 MiB + FFF0 bytes.

 * Note: FFFFF is hexadecimal and is equal to 1 MiB and FFF0 is equal to 64 KiB minus 16 bytes.

Moral of the story: From Real mode a program can actually refer to (1 MiB + 64 KiB - 16) bytes of memory.

Notice the use of the word "refer" and not "access". A program can refer to this much memory but whether it can access it or not is dependent on the number of address lines actually present. So with the 8086 this was definitely not possible because when programs made references to 1 MiB plus memory, the address that was put on the address lines was actually more than 20-bits, and this resulted in wrapping around of the addresses.

For example, if a code is referring to 1 MiB, this will get wrapped around and point to location 0 in memory, likewise 1 MiB + 1 will wrap around to address 1 (or 0000:0001).

Now there were some super funky programmers around that time who manipulated this feature in their code, that the addresses get wrapped around and made their code a little faster and a few bytes shorter. Using this technique it was possible for them to access 32 KiB of top memory area (that is 32 KiB touching 1 MiB boundary) and 32 KiB memory of the bottom memory area, without actually reloading their segment registers!

Simple maths you see, if in Segment:Offset representation you make Segment constant, then since Offset is a 16-bit value therefore you can roam around in a 64 KiB (or 2 to the power 16) area of memory. Now if you make your segment register point to 32 KiB below the 1 MiB mark you can access 32 KiB upwards to touch 1 MiB boundary and then 32 KiB further which will ultimately get wrapped to the bottom most 32 KiB.

Now these super funky programmers overlooked the fact that processors with more address lines would be created. (Note: Bill Gates has been attributed with saying, "Who would need more than 640 KB memory?", and these programmers were probably thinking similarly.) In 1982, just 2 years after 8086, Intel released the 80286 processor with 24 address lines. Though it was theoretically backward compatible with legacy 8086 programs, since it also supported Real Mode, many 8086 programs did not function correctly because they depended on out-of-bounds addresses getting wrapped around to lower memory segments. So for the sake of compatibility IBM engineers routed the A20 address line (8086 had lines A0 - A19) through the Keyboard controller and provided a mechanism to enable/disable the A20 compatibility mode. Now if you are wondering why the keyboard controller, the answer is that it had an unused pin. Since the 80286 would have been marketed as having complete compatibility with the 8086 (that wasn't even yet out very long), upgraded customers would be furious if the 80286 was not bug-for-bug compatible such that code designed for the 8086 would operate just as well on the 80286, but faster.

X86アセンブラ/16、32、64ビット

title: X86 Assembly/16, 32, and 64 Bits


text:
Talk:Danish/Lesson 1

- Edited page. The formal conversation named the speakers "Herre Nilsen" and "Herre Klaaborg", which is not correct. --Mjjohansen 16:39, 16 December 2005 (UTC)

Davs in formal conversation
I don't believe "davs" ("hello" ) is used formally – on the contrary it is a very informal greeting (but since spoken Danish is almost always very informal it doesn't actually matter very much). It is also falling out of use, and many young people would probably consider it archaic.

title: Talk:Danish/Lesson 1


text:
User:Mjjohansen~enwikibooks

Morten Juhl Johansen, Long-time Internet and Linux user.

title: User:Mjjohansen~enwikibooks


text:
User talk:192.195.154.107

Thanks for experimenting with Wikibooks. Your test worked, and has now been removed. Please use Sandbox for any other tests you want to do, since testing material in modules will normally be removed quickly. Please see the welcome page if you would like to learn more about contributing to our project. Thanks. -- LV (Dark Mark) 17:12, 16 December 2005 (UTC)

title: User talk:192.195.154.107


text:
Persian/Websites

Lessons
Modern Persian

 * Iraj Bashiri's Persian For Beginners
 * Virtual Persian
 * Grammaire Iranien PDF Grammaire Iranien (in French)

Old Persian

 * Iranian Studies at Harvard University

Online Dictionaries

 * Aryanpour's Persian-English and English-Persian online dictionary
 * A comprehensive Persian-English dictionary Francis Steingass's dictionary online, includes a guide to pronunciation.

Language Tools, Games and Software

 * Persian verb conjugator

Persian Media

 * Persian Media

 * BBC Persian
 * Radio France International
 * NHK Persian (Japan)
 *

Universities teaching Persian as a Foreign Language
Europe

 * University of Manchester
 * University of Cambridge

East Asia

 * Peking University School of Foreign Languages北京大學外國語學院東方語言文化係 (in Chinese)
 * Shanghai Foreign Languages Univeristy上海外國語大學 東方語學院 (in Chinese)

Middle East

America

Language Exchange

 * mylanguageexchange.com Find a Persian-speaking language exchange partner

Foundations and Trusts

 * Iranian Heritage Foundation UK
 * British Institute of Persian Studies UK
 * American Institue of Iranian Studies UK
 * Institut für Iranistik Institute for Iranian Studies, Austria

波斯語/聯結

title: Persian/Websites


text:
User talk:65.240.186.185

Welcome to Wikibooks, collection of open-content textbooks! You don't have to log in to read or edit articles on Wikibooks, but creating an account is quick, free and non-intrusive, requires no personal information, and gives you many benefits, including:
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We hope that you choose to become a Wikibooks and create an account. We hope you enjoy your time here on Wikibooks as a Wikibookian! -- LV (Dark Mark) 17:14, 16 December 2005 (UTC)

title: User talk:65.240.186.185


text:
User talk:Mjjohansen~enwikibooks

Hello and welcome to Wikibooks!

Here are some tips to help you get started:
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You will find more resources in Community Portal. If you want to ask a question, visit the Study help desk, the Staff lounge, or ask me personally on my talk page.

Good luck! -- LV (Dark Mark) 17:15, 16 December 2005 (UTC)

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title: User talk:Mjjohansen~enwikibooks


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Talk:Calculus/Print version

someone should put page numbers for this book, if it's finished. DettoAltrimenti 18:05, 16 December 2005 (UTC)

 * the book is certainly not finished. Page numbers would be a good idea, but I am not sure if it is possible Juliusross 00:34, 17 December 2005 (UTC)

thanks
is this book finished now? thanks to all for writing, but a quick note; i dont know if it can be fixed, but when i go print preview some of the math on the bottom of the pages is cut off and won't show up properly on print-out, could this be because of use of mozilla or??

Major sections and page breaks
I started adding page breaks between major sections so that when the printed version is previewed or printed, sections that are logically separate are physically separated. The highest level sections (e.g. Precalculus, Limits, Differentiation, etc) I have on their own page. It looks pretty sparse currently. What I envision is a page with the name of the major section (maybe in an artful font), maybe a graphic illustrating something relevant to the section, and maybe a brief introduction to the topics covered in that section. Unfortunately I don't have time to implement that currently. Maybe someone who has more time can work on it, or maybe if I get time later I can come back and work on it. --Greenbreen (discuss • contribs) 16:50, 21 May 2011 (UTC)

This page is far too big
Hi, This page is too big. The web browsers have difficulties to render it quickly/properly and the Wikibooks API simple refuses to do so, see https://phabricator.wikimedia.org/T191139. This content would be a lot easier to enjoy if it was split in (sub-)pages. Kelson (discuss • contribs) 16:49, 31 March 2018 (UTC)

title: Talk:Calculus/Print version


text:
Haiku/Introduction

What is Haiku?
In short, Haiku is an open-source re-creation of the operating system BeOS. In 1990, a company called Be Incorporated was found in California, USA, by ex-Apple employees Jean-Louis Gassée and Steve Sakoman. Be, Inc. had a vision: to create a powerful, elegant, media-oriented, and friendly computer with a matching operating system. They did create one. The computer was called the BeBox, and it and its operating system, the BeOS, were first presented at Agenda 95 in October, 1995. It made the audience go wild.

The BeBox was ahead of its time in many ways. In the middle of the 1990s, it was unheard of that a consumer PC would have more than one CPU. The BeBox had two CPU's; originally AT&T Hobbits, and from 1995 onwards PowerPC. The operating system, BeOS, had pervasive multithreading, pre-emptive multitasking, 64-bit journalling, database-like filesystem, very low latency in audio and video tasks, and a clean, slick user interface. It was, in a word, an operating system you could almost fall in love with.

Sadly, as things go, Be had to quit hardware due to financial and hardware supply problems, and they ported BeOS to PowerPC in 1997 and later, in 1998, to Intel compatible systems. Although the operating system had many enthusiastic users and developers, it never gained a significant market share. Lack of applications was one thing, as BeOS was developed from scratch and had only partial POSIX compatibility. In 2000, Be released the BeOS version 5.0, called the Personal Edition, for free (as in freeware) on the Internet – which undermined the sales of the Pro edition, increasing Be's financial difficulties. The company shifted its focus to Internet appliances, which eroded the credibility of BeOS as a viable alternative to Windows or Linux. Be, Inc. went bankrupt in 2001.

Be left a legacy: a free of charge version of the BeOS. Although the operating system's future looked bleak, many still wanted to use it daily. From that want rose several projects to re-implement the BeOS experience in open source. Haiku is one of them.

Haiku is Japanese and means a short poem of a certain type. Originally, when the project was started in late 2001, it was called OpenBeOS; later, it was renamed Haiku. Haiku poems are simple and elegant, and that is what the Haiku Operating System also strives to be. The goal of Haiku is to be source and binary compatible to BeOS 5.0, and then extend it further to new areas. Because of the modularity of BeOS and because a free of charge, usable version was available, it was not an impossible task to start recreating the operating system.

At the time of writing this introduction (Dec 2005), Haiku has advanced slowly but steadily. The first working, alpha version seems to be just around the corner.

Purpose of this book
What you are reading now is the Unofficial Haiku Handbook – a user manual. This book will guide you in installing and using Haiku, configuring it, installing software, connecting to other computers, playing media files, and managing your files efficiently. Although it is written more from the beginner's perspective, many old, advanced BeOS users will no doubt find useful hints. Haiku R1 is very similar to BeOS 5.0.

FIXME: Add description of chapters once the table of contents has been fixed.

Additional documentation
The official Haiku user guide and other documentation pages can be found at the Haiku website. Although ancient, part of the documentation efforts made for BeOS could still be relevant to the usage with Haiku. Among these sources, could be mentioned:
 * — for power users and professionals
 * — for programmers of applications or system add-ons using the BeAPI

Acknowledgements
The authors would like to thanks the readers of this book, to the community and developer team of Haiku, and also to the adventurous who give Haiku a try.

title: Haiku/Introduction


text:
Talk:A-level Mathematics/OCR/C1/Differentiation

Someone merged another page, A-level Mathematics/C2/Differentiation, into this page. You can view the [ edit history of A-Level Mathematics/C2/Differentiation].

Differentiation is NOT in C1
Sorry to all you guys that have put this here, but I have just checked the OCR syllabus, there is no mention of Differentiation at all.

It's deff in the Edexcel syllabus...

-- It's DEFINITELY in the OCR syllabus. We just did about 2 weeks of it and it's in my OCR book. 82.20.215.203 (talk) 17:37, 15 November 2008 (UTC)

From Talk:A-level Mathematics/C2/Differentiation
Hi, I've just added quite a bit on differentiation. It could probably do with some editing and probably re-writing. This is my first real addition to wikibooks so sorry if it isn't that good ^^. Anyway, there is still more that is required based...However it appears in C1 I believe, not C2, so perhaps someone could move this page unless I am mistaken. I was also wondering...would it be possible to add multiple index pages so that this book could cover multiple syllabuses, since that basic differentiation is also what I did on AQA for P1 as I recall. Anyway, hope what I put is at least some use as a foundation, bye for now. Robb3h 19:10, 27 July 2005 (UTC)

No problems, im fairly new to wikibooks myself. I just checked my textbook and it appears in chapter 8 under a C2 tab, i had previously moved it from C1 to here. I thought the textbook I have covers all examining bodies. P1 is a mix of C1 and C2. The alternative index pages seem like a good idea, that only leaves the question of which index page will be the main one. Krackpipe 13:45 29 July 2005

I'm in the second year of my OCR Maths A-level, and last year differentiation was definitely C1 (and still is, I hasten to add). I don't want to move anything without some consensus, but it would seem it should be under C1... Odd bloke 00:48, 23 November 2005 (UTC)

Differentiation definately under C1 - doing AS and covered it very recently. However I think there is more differentiation under C2 - perhaps a seperate topic for that.

 * Take a look at my talk page, this issue has been resolved, and differentiation is in fact in C1. I moved it by accident because I confused two different, but similarly named, specifications from the same examining group.--Krackpipe 19:49, 6 December 2005 (UTC)

Related Rates
The solution to the moving ladder problem uses implicit differentiation (not covered until C4?) and seems too complicated for C1. I can't see a way to solve this problem using only C1 differentiation, so perhaps it should be changed/removed. Aleksev 18:18, 16 December 2005 (UTC)

This still needs a LOT of work. There is absolutly NO explanation of what exactly a derivative is. The module jumps right to the power rule, bypassing the basis of derivatives, which are really the limit of a secant line. Pictures wouldn't hurt either.--Crucible Guardian 21:09, 18 December 2005 (UTC)

A Suggestion
I am not familiar with A-Level Mathematics, so of course, I cannot do this myself. However, it would be nice if a proof for the different rules was shown alongside the rules, unless they are postulates. Which I assume they cannot be.

bath tub example.
i think the bath tub example is probably a bad one. the maths is sound, but the example is confusing because a bath would never fill at such a rate. unless you have very odd plumbing the bath will almost certainly fill at a constant rate. something like the acceleration of a car makes much more sense and would be easier to understand.

Good Idea Fixed. Keytotime 18:09, 5 November 2006 (UTC)

Differentiation IS in C1
look at page 8 in the spec

Afraid not...
Look at the date on that spec. I'm doing C1 / 2 now and I know for a fact that C1 has been done and dusted for a month and only now are we doing Differentiation. It is in C2


text:
User talk:146.151.109.121

Thanks for experimenting with Wikibooks. Your test worked, and has now been removed. Please use Sandbox for any other tests you want to do, since testing material in modules will normally be removed quickly. Please see the welcome page if you would like to learn more about contributing to our project. Thanks. -- LV (Dark Mark) 18:45, 16 December 2005 (UTC)

title: User talk:146.151.109.121


text:
Learn Electronics/Digital Circuits

=Digital Circuits=

Digital electronics handles digital signals. Digital signals are discrete signals. They have constant amplitude for a specific time period. Digital Circuits are a very important part of Electronics, and learning at least their basic concepts is highly recommended.

=See also=
 * Digital Circuits
 * Elements of Digital Circuits
 * TTL NOT and AND gates, just simple examples of the very many digital circuits.
 * Analog circuits for comparison with digital circuits and digital Integrated Circuits (ICs).
 * Digital to Analog & Analog to Digital Converters
 * Communication systems Pros and Cons of Digital versus Analog.
 * Digital Television and Mass Media
 * Digital photography
 * Electronics/Expanded Edition
 * Signals and Systems/Time Domain Analysis/Sampling Theorem

From Wikipedia:
 * Category (digital)
 * Digital (the concept)
 * Digital circuits
 * Digital control
 * Analog-to-digital converter
 * Digital-to-analog converter
 * Digitizing requires circuits to turn an analog signal into a digital representation of that signal.
 * Digitizer converts an analog signal into a digital representation of the analog signal by sampling the analog signal.
 * Electronics topics

From the Web:
 * http://www.dspguide.com/filters.htm for "Introduction to Digital Filters". An example of what digital circuits are needed for.

Previous chapter ../Analogue and Digital/ | Next chapter: ../Microprocessors/ | Go back to Index

title: Learn Electronics/Digital Circuits


text:
User talk:68.74.78.189

Welcome to Wikibooks, collection of open-content textbooks! You don't have to log in to read or edit articles on Wikibooks, but creating an account is quick, free and non-intrusive, requires no personal information, and gives you many benefits, including:
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title: User talk:68.74.78.189


text:
High School Physics/Electric Circuits

"Once upon a time, there were two types of people. The people of toaster town and the people of Glove town. Every so while, a person from each town would observe each others differences, perhaps wanting to move to live a lifestyle which is good for them. People from toaster town observed that people in glove town typically "had no energy." The people of the town were very slow moving and conservative. They tended to resist the advances in Toaster town because they thought "Energy will destroy the very meaning of our life." Thus, they enacted the "no moving electrons" law and thus all the people in the town stayed at home, preferring to abundantly stare at the wall.

Similarly, the people from Glove town observed that people in Toaster town tended to have "lots of energy." Being liberal, they embraced the concept of "energy" and typically have places called "Energy bucks" to give them energy to live their fast placed life. Everybody tended to walk very fast and seemed to work as delivery people, giving "current" to others and living their own happy lives.

$$\text{Ohms Law}:R=\frac{E}{I}$$
 * (higher) resistances, (Less) current
 * (lower) resistances, (higher) current

Similarly, the people of both the towns are there to represent a key point in electrical circuits: Ohm Law. What basically Ohms law says is that if the resistance is higher, than the current will be lower. Conversely, if resistance is lower, than the current will be higher. As you you can see, there are generally two types (in actuality there are more, but for the sake of learning) Inductors and conductors. Inductors, as represented as "glove" town, tend to have very high resistances and don't tend to pass too much electrons from one point to another. Conductors, as represented as "Toaster" town, tend to have lower resistances and pass electrons of current easier easier.

Atomic Representation of Inductors.

(ex) Heavy metal Concerts: no passes

Inductors are basically molecular "bouncers" that don't tend to accept electrons from one point to another.

Atomic Representation of Conductors.

(ex) Heavy Metal Concerts: with passes

Conductors are like the young, rich, electrons that pass freely through the metal gates and thus enjoy the concert freely.

Just in case you didn't know: Don't touch the inside of your computer without touching metal!!

The most apparent form of electricity for a majority of mankind has been this force called "static electricity." As young children, we used have fun and rub our feet over the carpet and thus shock our friends which this intense shock (though, not enough to harm you). As you have grown older, likely you would have gotten this shock when touching your car door. Here is an experiment in which you want to consider.

FEET (hippy like conductors) Try this experiment with no shoes and rub your feet across a carpeted area. Feel the shock!

Shoes (for conservative inductors)

Try this experiment with rubber boots. Now, rub your feet across the carpeted and feel....well nothing.

title: High School Physics/Electric Circuits


text:
Talk:Blender 3D: Noob to Pro/UV Map Basics

I was unable to do the steps
I am very noob. There is no CTRL+UKEY. Never, nowhere. To refer to a key on the keyboard is 'push the key Ctrl+U on your keyboard' (because I am very nooooob. :| ) in MS Office, in Linux, in Mac and in everywhere in the internet. Don't write 'ensure that you are in edit mode then press UKEY'. Write this: ' 1. Select x window. 2. Select 'Edit Mode' in drop-down menu. 3. Push 'A' key on your keyboard as many times till object will be selected. 4. Push 'U' key on your keyboard to unwrap the object… With before-after images!! This step-to-step method is for noobs like me. :|

 * The keyboard notation is described in Blender 3D: Noob to Pro/Keystroke, Button, and Menu Notation, which you should read as it's early on in the book. Also, if you do find the notation confusing, then fix it.  --Sigma 7 (discuss • contribs) 17:29, 17 January 2013 (UTC)

Incredibly verbose, does not get to the point
I am new to Blender and this wall of text provides so much of a challenge to get past I cannot get past it. Really, a n00b does not need to know everything that is happening. Just show with just the text needed in incremental steps how the process is done. As it stands now it is more confusing than anything. I don't even know where to start from a reference point of view either.

Can I write this chapter
Does anyone mind if I write this chapter? If not where can I put screen shots. After watching the Video I had a better idea of how to do UV Mapping but I still had a hard time unwraping a simple box. I imagine that other noobs like me would have the same problem so I just wanted to write a small one that shows how to map a box. Then maybe a more complex object (like an H made of boxes) —The preceding unsigned comment was added by Ripter (talk • contribs) 04:32, 17 December 2005.

 * I think that would be great. I was unclear on how or even if the spaces between vertices could be adjusted so that it could be used on a character's face like with a Make Human mesh. Also I wasn't sure how to export that to an image editor such as Photoshop and how to reapply it to the mesh.
 * Byron —The preceding unsigned comment was added by 24.151.244.113 (talk • contribs) 12:17, 9 January 2006.

LordOfer changes
I read this chapter and I made some changes. Since I'm still a bit new to blender I think it's best if someone looked over the stuff I changed, because I'm only 99% sure about some of them. Also, I deleted few lines of chat between two users. I just thought I should...

LordOfer —The preceding unsigned comment was added by LordOfer (talk • contribs) 22:57, 17 August 2006 (UTC)

UV
What does UV stand for? --Remi 19:05, 2 June 2007 (UTC)

 * I want to know too 217.36.120.131 10:30, 12 August 2007 (UTC)

 * The UV in UV mapping is just the two directions, as X and Y are used in 3d, it was decided to use the next closest letters for the 2d image mapping.
 * (or something like that) —The preceding unsigned comment was added by 203.89.172.85 (talk • contribs) 13 August 2007 (UTC)

 * Yes. For technical reasons related to 'homogeneous coordinates' you need four numbers to describe a 3D vertex.  Hence, 3D graphics people use X,Y,Z and W for 3D coordinates.  In the early days of texture mapping, U and V were the logical choice because they are the immediately previous letters in the alphabet before W.  However, blender is a bit behind the times because with modern hardware you can have 3D textures - which means you need another letter (and with 'homogeneous texture coordinates', two more letters).  In modern shader languages (Cg, GLSL, HLSL) S,T,P and Q are used for texture coordinates (R is not used because it gets confused with the 'R' in RGBA.  Hence, the 'modern' nomenclature ought to be 'ST' or 'STP' mapping...but many engineers and almost all artists still talk about "UV mapping" out of habit.  SteveBaker (talk) 18:57, 22 June 2008 (UTC)

How to separate the unwrap?
when adjust the mesh to the pic of earth, you kind of separated the mesh. (there is a red and a green edge in the screenshot). it would be good to explain i think.

gez. cassul —The preceding unsigned comment was added by 137.193.187.73 (talk • contribs) 11 October 2007 (UTC)

No Sense
This page makes no sense, probably since blender has been updated. What the heck is an RMB? And some of the windows I can't find. And the author should keep in mind that noobs don't know how to do anything! —The preceding unsigned comment was added by 75.137.124.50 (talk • contribs) 14:30, 12 January 2008 (UTC)

 * Even newbs should be able to read the instructions at the beginning of the tutorial. It clearly says on the first or second page (the one that explains what all the abbreviations will be) that RMB is Right Mouse Button.  And DO try to read all the instructions before you go and complain.  HydraZulu (talk) 17:30, 26 February 2008 (UTC)

 * Try downloading an old version or recommending an update? 9:73AM, 19 October 2008

no "UV Face Select" window mode?
I cannot find this window mode in Blender 2.46--5o (talk) 17:30, 10 June 2008 (UTC)

 * Neither can I - but I think everything works OK if you leave the thing in Edit Mode.

 * This entire WikiBook needs to be fixed up for more recent editions of blender.  The problem is that most newbies will be downloading the latest and greatest version - so it's hardly necessary to talk about the older versions of blender that are out there - but keeping up to date with the latest changes is vitally important because otherwise we noob's will continually hit roadblocks like this when trying to follow the instructions. SteveBaker (talk) 19:02, 22 June 2008 (UTC)

Python script error?
When I try to save the unwrapped mesh by going to UVs -> Scripts -> Save UV Face Layout, I get a Python script error. Anyone know what this is about? —The preceding unsigned comment was added by 157.127.124.14 (talk • contribs) 06:24, 2 October 2008 (UTC)

Blender 2.48a on Ubuntu 8.04 (Hardy Heron): I get no response, erroneous or otherwise when using UVs -> Scripts -> Save UV Face Layout. Instead I used the image provided, selected a hemisphere from the 3D view, then positioned the half of the unwrapped mesh in the UV Image Editor view over one of the image hemispheres, then repeated for the other. I ended up with a passable blue marble.

Unexpected
As a new user to Blender, I have been using 2.45 up until quite recently. Perhaps a mention of what to expect? From 2.45 to 2.48a. When you unwrap there is an active face, but if you are not expecting that active face to be missing in UV unwrap and appear to be missing in 3d view. It can be off putting for new people, as they think: "What have I done wrong now?" —The preceding unsigned comment was added by 90.214.110.98 (talk • contribs) 18:39, 19 February 2009 (UTC)
 * That is exactly what happened to me! Thank you for explaining that weirdness SirSuki (discuss • contribs) 06:49, 1 December 2013 (UTC)

UV sphere
Perhaps this tutorial would work better with a UV sphere instead. Just my two cents. —The preceding unsigned comment was added by 70.115.234.192 (talk • contribs) 11:16, 24 February 2009 (UTC)

Rectangular UV Map
You can also use a normal rectangular pic of the earth and unwrap it. I started with a satellite image of the earth from maps.google.com, without labels. I opened it in the UV Image editor, and unwrapped. Then I took the two polygons and moved some of the pixels, pushing them into the center and into the corners to fill completely the rectangular picture. This wraps and renders quite nicely, with a bit of fiddling of the pixels, and happens to be better than the supplied images in this tutorial which are not complete halves of the earth, but approximately thirds, so are missing most of the southern hemisphere. You can also photoshop the rectangular image and remove the Google text so it doesn't show up on your rendered earth. Nanobug (talk) 02:35, 24 October 2010 (UTC)

Page Layout
With Blender 2.49b being standard and 2.5x nearing completion, shouldn't the "2.49b" section be moved to the top and renamed, followed by sections dealing with versions prior to the 2.49b release?

I agree. At the risk of complication and server space it might even be worthwhile to have two chapters addressing the same subject. The first should have a title making it clear it is for versions before 2.45. The other's title should explicitly say it is for version 2.49 (and later). I have 2.49. The video on UV mapping is very well presented and everything works logically with great facility. Unfortunately, in my case, the commands no longer are in version 2.49.WindsorSpring (discuss • contribs) 15:20, 20 February 2011 (UTC)

Should anything else be added to this?
Hi everyone, I've just finished updating this page to the 2.6x series. Does anyone think more content should be added to this page? e.g a section for Blender's new box mapping feature/descriptions of the other unwrapping options?

Would be interested to hear your ideas...

JamesNZ (discuss • contribs) 08:25, 2 November 2012 (UTC)

Texture coordinates missing UV selection
With Blender 2.68a I am unable to select "UV" in the Texture > Mapping > Coordinates select box. Is there a missing step to activate this? My render does not include the texture without this. SirSuki (discuss • contribs) 06:53, 1 December 2013 (UTC)

 * Answering my own question. You have not click on the world texture but be sure you're on the material texture. This means the current screen shot is incorrect! SirSuki (discuss • contribs) 06:58, 1 December 2013 (UTC)

wraparound to use the whole picture
In the alternative method, one does not want the UVs to go out of bounds vertically. However, it is actually desirable to go out of bounds horizontally and wrap around, specifically to have as much out of bounds on the left at each vertical position as the mesh falls short on the right, and vice versa. That way the whole map is used. The mistake is evident in the final screenshot in the fact that Russia crashes so completely into Alaska, because the edges simply aren't used. Ehsanit (discuss • contribs) 10:55, 24 December 2014 (UTC)

Mark a Seam -- why?
And why there in particular? I could form deductions from my limited information as to why you assume it to be self-evident, but perhaps you could share the benefit of knowledge gained from experience which qualifies you to offer tutorials in the first place?