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Talk:Investigating 3D geometric algebra

Tone of the article
This page intentionally uses familiar concepts such as metres rather than the more abstract 'unit length' to aid understanding. I hope this is ok...

title: Talk:Investigating 3D geometric algebra


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Talk:Introduction to Calculus/Differentiation

This is good as a study sheet to supplement a lesson plan. To make it a lesson plan, one has to motivate the definitions as well as prove theorems. Pretend that you're preparing a plan for an actual class of students. Why should the student want to define the derivative in that manner? PS. Also, it is rather backwards to note that the derivative of ln(x) is 1/x, as ln(x) was defined as the integral of 1/t dt from 1 to x, as this integral, a "hole" in the power rule, was found to behave like a logarithm if one gave the logarithm the base e. The discovery of this fact would make a great exercise sheet. For more info on the history of ln(x), see "e: the Story of a Number" by Maor. Ron 01:56, 23 August 2006 (UTC)

Pedagogy
Hey Hypermorphism. I wanted to thank you for taking interest. I am sort of in the process of trying to make what I wrote make a little more sense and be a little more pedagogical, and I was hoping others would help out, but in the meantime I figured I'd post what I had, to get this ball rolling. Feel free to add examples or change my sometimes awkward phrasing. That's what wiki's for right? Anyway, I'll see what I can do.

By the way, I disagree that it's backward or redundant to discover the derivative of ln the way I did. There are a number of equivalent ways to present ln(x) and it is a matter of taste what to call a definition and what to call a result (as long as there's only one of the former of course). I was taking as the definition of ln(x) that it was the inverse funciton of $$e^x$$, or in other words that the statements $$ln(x)=y$$ and $$x = e^y$$ are equivalent. Daniel M. Roberts 02:26, 23 August 2006 (UTC)

 * I don't quite understand why there is so much emphasis on e? --HappyCamper 04:35, 23 August 2006 (UTC)

Reply
Hey Daniel, I was just nitpicking, as mathematicians are wont to do. :-) I like exposing the history of mathematics as much as possible to the student, in order to humanize a topic that may sometimes seem sterile of human foibles. Most textbooks and courses never talk about the historical development of the subject in any amount of detail; they present only pristine results and well-polished "remarkable" relationships. Many students are unaware that calculus only recently went through two revolutions of rigor after the initial formulation, where hand-waving was the norm when it came to the actual machinery. The players (Ie., Kronecker with his "God created the integers. All else is Man's invention.") were fascinating, but that level of detail is for another course. I would only just comment on little stuff like the meandering discovery of e. :D

 * I might do some little additions here or there, but I'll be focusing on building a series of lessons that start from defining the real number system (the playground) that then naturally leads to limits, from which derivatives and integrals are only one leap of logic away. Keep creating lessons! :-) Ron 02:46, 23 August 2006 (UTC)

 * Hmm. That's interesting what you have to say about math and math history. I've done a little bit of research in the past on the history of calculus, although you probably have more of that than I do. Anyway, I'm hoping to add the kind of stuff you were talking about, after I get the basic skeleton of the page down. I know what you mean about glossy-eyed kids uhuh-ing their way through a lecture. Again, feel free to pose some take-a-step-back kind of questions or a few excersizes along the way if any come to mind. Thanks for your ideas. I mean, of course you're right. Daniel M. Roberts 04:29, 23 August 2006 (UTC)

 * As an example, the fact that we are studying calculus is highly nontrivial - for example, the Greeks were not able to understand limits the way we do today. We should be very thankful that so many great minds thought carefully about these things!! --HappyCamper 04:33, 23 August 2006 (UTC)

Duplication
Hmm...better be careful that this doesn't duplicate Calculus/Differentiation too much... --HappyCamper 05:09, 23 August 2006 (UTC)

Reorganization
Hey HappyCamper, thanks for the reorganization you did last night. The only thing I would change is the placement of the whole compound-interest excursion. I know it makes sense to you and to me to jump right into what a derivative is and what all its rules are, but imagine how much sense that would make if you had never been exposed to that. To me the point of the compound-interest excursion was to warm them up with It may seem like an arbitrary way to lead up to derivatives, but I think it's important in that it submerges the abstract talk in a context that is obviously related to real life.Daniel M. Roberts 16:46, 23 August 2006 (UTC)
 * The idea of functions (i.e. the relationship between one variable and another)
 * The idea of limits and why you would ever use them
 * A knowledge of binomial expansion, which is necessary to prove a number of things including the $$x^n$$ rule
 * Finding a friend in $$e$$ so that when they get into the later section about transcendental functions etc, they already see a familiar face.

 * Hmm...the binomial expansion is not necessary to derive the Power Rule - it can be done with the chain rule and induction. Then, one could make a "leap of faith" and say that it works for arbitrary n. This of course, can be stated in the article.

 * Euler's number is not quite so fundamental for limits and such - its derivation does not address notions of existence of a limit, continuity, or differentiability. I can understand why it is introduced so early, but from my perspective, it is presented too soon for it to be useful.

 * As for familiarity, I think a variety of examples would suffice. Generally speaking, newcomers to calculus do not have the notion of piecewise continuous functions yet.

 * What I'm worried about now, is whether this is duplicating the effort over at Wikibooks... --HappyCamper 17:22, 23 August 2006 (UTC)

 * I know what you mean about all that stuff, but I don't know if you remember learning calculus or not (sometimes I hardly do) but back then, the last thing that you wanted to know about was the formal epsilon-delta formulation of the limit, for example. That goes for smaller things too. It's okay to gloss over the difference between piecewise and non-piecewise continuous functions for example to begin with and bring up the discussion about continuity and differentiability after it is motivated by the knowledge of what a derivative is. As for the importance of $$e$$, I would argue that it is at the heart of calculus and has the interesting quality that without calculus, it's just a number, and with calculus it is God's number. That type of thing I think can be cool to someone just learning calculus.Daniel M. Roberts 17:37, 23 August 2006 (UTC)

 * I wasn't thinking of an epsilon delta proof - this set of notes seems more like a set of notes for high school students. I actually still have mine, and all the pieces of scrap paper where I was struggling with everything. Well, I'm not very keen on where this e stuff is located at the moment, but since I'm not being too productive with editing the article, I guess I'll leave it as is. There are other gaps I want to fill in, like these differentiation rules for general exponentiation. But sooner or later, I suspect that "units" of knowledge will be split into its own pages, and when lesson plans are drawn up, one can simply say that we'll learn units 1,2,3,16,17 in perspective X, and 1,4,5,6,7 in perspective Y. --HappyCamper 17:54, 23 August 2006 (UTC)

 * Sounds good to me. I mean you're right, it'll probably be split up and there's a lot to add anyway before we can see how to organize it. Anyway, thanks for working on it with me. --Daniel M. Roberts 23:03, 23 August 2006 (UTC)

I'm a little dubious about this explanation:

 * $$1+r+\frac{r^2}{2}+\frac{r^3}{3!}+\frac{r^4}{4!}+\dots = \lim_{n\rightarrow \infty}\bigg(1+nr\bigg(\frac{1}{n}\bigg)+\frac{nr(nr-1)}{2}\bigg(\frac{1}{n}\bigg)^2

+\frac{nr(nr-1)(nr-2)}{3!}\bigg(\frac{1}{n}\bigg)^3 + \dots \bigg)$$

First of all, the fact that the k-th term of the expansion of the binomial converges to $$\frac{r^k}{k!}$$ is not sufficient to justify the limit under the infinite sum. (Otherwise, on the same line, 1= 1/n + 1/n +..+ 1/n (n terms) would converge to 0+0..+0=0 ) We need a dominate convergence principle for series, which is indeed available, but it would be more correct at least to mention it.

 * $$ = \lim_{n\rightarrow\infty}\bigg(1+\frac{1}{n}\bigg)^{nr} = \Bigg(\lim_{n\rightarrow\infty}\bigg(1+\frac{1}{n}\bigg)^n\Bigg)^r = \bigg(1+1+\frac{1}{2}+\frac{1}{3!}+\frac{1}{4!}+\dots \bigg)^r$$

Second, here we are using an expansion where r and n are positive integers (unless we are using an even less elementary tool, the binomial series). Why should the expansion be valid for r=√2? --PMajer (discuss • contribs) 20:44, 16 December 2018 (UTC)

Quiz
Need a quiz? I would love to try out the ABCD template some more.--Rayc 01:32, 22 September 2006 (UTC)

 * Yes, yes, yes :-) Can we do something like this?

 * Q: What is the derivative of x?
 * A) 1
 * B) 0
 * C) x
 * D) none of the above

 * --HappyCamper 03:21, 28 September 2006 (UTC)

Under the heading of Implicit Differentiation, you make reference to the quotient rule (i.e. 'One could find [the derivative] with the quotient rule...') without ever having mentioned what the quotient rule is. If you're going to mention it (which you may choose not to), you ought to show it (i.e. as an application of the product rule).

explicite multiplication signs
Consider including multiplication signs in the formulas.

For
 * $$A=A_0(1+\frac{r}{n})^{nt}$$

write
 * $$A=A_0\cdot \left(1+\frac{r}{n}\right)^{n\cdot t}.$$

Bo Jacoby 19:20, 29 September 2007 (UTC)

Proposals
Hi sirs! I just jumped into this, as User:Un-predictable was asking me for help in derivatives. There's so much work already done here! Congrats for your job!

I have thought of a few proposals, and wanted to know your opinion:

When I was taught this, the letter h was also used for the shrinking difference in x. But looking backwards, I think it's easier to understand the formulas if instead of h we write $$\Delta x$$, which is already used when talking about slopes. (I know it's important to teach that bound, or dummy, variables can be called whatever; but being able to doesn't mean it's a good idea, and in this case the name $$\Delta x$$ carries semantic meaning).

Another thing I think would improve the lesson is the inclusion of tons and tons of graphics, depicting e.g. a function f(x), a couple of points f(x) and f(x+h), and such things. I am myself a visual learner, and understand things a lot quicker if I can see or imagine them. I think I could do some graphics on Matlab (I don't have Mathematica installed right now), but I doubt I'd be able to put the labels and colors needed to make it pedagogical. I also ignore the license issues regarding a graphic produced by those programs (which I don't own legally). Is there any software to create such graphics, as are seen in the textbooks?

When teaching derivatives to my cousin I found that it made it easier to present them to him like this (with the aid of a sheet of paper to draw):

$$f'(x) = \lim_{\Delta x \rightarrow 0} \frac{f(x+\Delta x)-f(x)}{(x+\Delta x) - x} = \lim_{\Delta x \rightarrow 0} \frac{\Delta f}{\Delta x} = \frac{df}{dx}$$

That made him understand $$d w$$ as a shorthand for "$$\Delta w$$ when $$\Delta w \rightarrow 0$$". And some properties were made easier to demostrate, e.g. the product rule:

$$\frac{d\left(f\cdot g\right)}{dx} = \frac{\left(f+df\right)\cdot \left(g+dg\right) - f\cdot g}{dx} = \frac{f\cdot g + df\cdot g + f\cdot dg + df\cdot dg - f\cdot g}{dx}$$

$$ = \frac{df\cdot g + f\cdot dg + df\cdot dg}{dx} = \frac{df}{dx}\cdot  g + f\cdot \frac{dg}{dx} + \frac{df}{dx}\cdot dg$$, with this last term going to 0 with dg

It is probably longer than the definition using limits, but it made him see it less like magic but like something reasonable. (It also aided much a picture of a rectangle of sides f and g which was prolonged by df and dg, being the third term up here the little rectangle df·dg which appears in the corner).

Has anybody at wikiversity tried yet ways to present different explanations for the same thing?

Good day --Jorge 15:11, 13 April 2008 (UTC)

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


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User talk:IlyaHaykinson

Messedrocker 02:05, 23 August 2006 (UTC)

title: User talk:IlyaHaykinson


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Wikiversity:Education

This page gives a summary of various education topics as they relate to Wikiversity.

Nature of Education
Education is the development of individuals' capacity to realize various cultural goods and become a successful member of a society. Formally it encompasses teaching and learning specific knowledge, beliefs, and skills. Informally, it is the process of embibing ways of living and knowledge that are taught by parents and other members of the student's culture.
 * Inquiry and discovery
 * Collaboration and dialog
 * Online learning
 * Training

Levels of Education

 * Preschool through high school
 * Technical and Further Education (Training)
 * Undergraduate
 * Graduate
 * Continuing education

Wiki Pedagogy

 * Learning projects.
 * Learning to learn a wiki way - how best to use wiki technology in education
 * There exists a paper on One Laptop Per Teacher (OLPT), where the research question is "How can One Laptop Per Child be used as One Laptop Per Teacher?"
 * A paper on a constructivism approach called PedaGlue is being drafted.
 * Dialogical and critical learning

Education Communities
Communities of practice is a short introduction to the ideas of Jean Lave and Etienne Wenger. They proposed that learning is social and comes largely from our experience of participating in daily life. Their model of situated learning proposed that learning involved a process of engagement in 'communities of practice'.

Education Research

 * Evaluation
 * Participation and co-learning
 * Action research

Experts or Expertise?
Wikis are collaborative spaces, and therefore require the contribution of many different types of people, from various backgrounds. Some people will be more knowledgeable than others in certain areas - these people might be viewed (or view themselves) as "experts". Alternatively, they might be said to have expertise, i.e., specific knowledge about something, rather than conform to the notion of what an "expert" is. Without necessarily challenging the notion of "expertness", it is possible to develop a wider conception that includes a process of developing expertise, rather than holding the status of "expert" as something fixed and far-ranging. It is true that experts have particular skill at seeing patterns and forming mental models (Bransford et al., 1999), but consider also the following statement about how we view the subject, and how this could inform a broader picture of "expertness":

 * "People's mental models of what it means to be an expert can affect the degree to which they learn throughout their lifetimes. A model that assumes that experts know all the answers is very different from a model of the accomplished novice, who is proud of his or her achievements and yet also realizes that there is much more to learn." (Bransford et al., 1999)

title: Wikiversity:Education


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Electric Circuit Analysis/Kirchhoff's Voltage Law

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Circuit Analysis Part II (Laws & Theorems)
This part is an introduction to some useful Electric Circuit Laws and theorems. You are encouraged to master the theorems and laws that will be discussed herein as they form a basis upon which most Circuit analysis methods are built.

Lesson Review
What you need to remember from Previous Lessons.

 * Review all lessons thus far ( i,e Read and be sure you understand lesson reviews done thus far )

Lesson 5: Preview
This Lesson is about Kirchhoff's Voltage Law. The student/User is expected to understand the following at the end of the lesson.

 * Remember what was learned in Passive sign convention, You can go back and revise Lesson 1.

 * Define Kirchhoff's Voltage Law ( word-by-word ).

 * Kirchhoff's Voltage Law: $$\sum_nv_n = v_4 + v_1 + v_2 + v_3 = 0$$

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 * }

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Part 1: Kirchhoff's Voltage Law
Kirchhoff's Voltage Law states: The algebraic sum of the voltages around a closed circuit path must be zero.

Notice that a closed circuit path insists that if one circuit element is chosen as a starting point, then one must be able to traverse the circuit elements in that loop and return to the element in the beginning.

Mathematically, The Kirchhoff's Voltage Law is given by

 * $$\sum_nv_n = 0$$

For reference, this law is sometimes called Kirchhoff's Second Law, Kirchhoff's Loop Rule, and Kirchhoff's Second Rule.

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Part 2:Kirchhoff's Voltage Law (Cont...)
We observe five voltages in Figure 5.1: v4 across a voltage source, and the four voltages v1, v2, v3 and v5 across the resistors R1, R2, R3 and R5, respectively. The voltage source and resistors R1, R2 and R3 comprise a closed circuit path, thus the sum of the voltages v4, v1, v2 and v3 must be zero:
 * $$\sum_nv_n = v_4 + v_1 + v_2 + v_3 = 0$$

The resistor R5 is outside the closed path in question, and thus plays no role in the calculation of Kirchhoff's Voltage Law for this path. (Note that alternate closed paths can be defined which include the resistor R5. In these cases, the voltage v5 across R5 must be considered in calculating Kirchhoff's Voltage Law.)
 * }

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Part 3
Now, if we take the point d in the image as our reference point and arbitrarily set its voltage to zero, we can observe how the voltage changes as we traverse the circuit clockwise.

Going from point d to point a across the voltage source, we experience a voltage increase of v4 volts (as the symbol for the voltage source in the image indicates that point a is at a positive voltage with respect to point d).

On traveling from point a to point b, we cross a resistor. We see clearly from the diagram that, since there is only a single voltage source, current must flow from it's positive terminal to its negative terminal--clockwise around the circuit path. Thus from Ohm's Law, we observe that the voltage drops from point a to point b across resistor R1.

Likewise, the voltage drops across resistors R2 and R3. Having crossed R2 and R3, we arrive back at point d, where our voltage is zero (just as we defined). So we experienced one increase in voltage and three decreases in voltages as we traversed the circuit.

The implication from Kirchhoff's Voltage Law is that, in a simple circuit with only one voltage source and any number of resistors, the voltage drop across the resistors is equal to the voltage applied by the voltage source:

 * $$v_4 = v_1 + v_2 + v_3$$

Kirchhoff's Voltage Law is a direct result of the electromagnetism force being a conservative one, i.e. the work done by the force on an electron is independent of the route taken, and depends only on the endpoints of motion. This is analogous to the electrons in circuits experiencing voltage drops and rises across circuit elements, and so KVL is true for any closed loop where the net displacement of an electron following the path of the loop is zero.

Kirchhoff's Voltage Law can easily be extended to circuitry that contains capacitors.

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Part 4 : Example
Consider Figure 5.2 with the following Parameters:
 * $$V_1 = 15V$$
 * $$V_2 = 7V$$
 * $$R_1 = 20\Omega$$
 * $$R_2 = 5\Omega$$
 * $$R_3 = 10\Omega$$

Find current through $$R_3$$ using Kirchhoff's Voltage Law. Solution:

We can see that there are two closed paths (loops) where we can apply KVL in, Loop 1 and 2 as shown in figure 5.3

 From Loop 1 we get:
 * $$V_1 - V_{R3} - V_{R1} = 0$$

From Loop 2 we get:
 * $$V_2 + V_{R3} - V_{R2} = 0$$

A bit confused? Sorry. But look at the explanation in Part 3 of this lesson and review the ../Passive Sign Convention/.
 * }

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Part 5 : Example (Continued)
The above results can further be simplified as follows:

$$V_1 - (I_1 - I_2)*R_3 - I_1*R_1 = 0 $$ $$I_2 = \frac{I_1\times{(R_3+R_1)} - V_1}{R_3}$$ ..... (1)

and $$V_2 + (I_1 - I_2)*R_3 - I_2*R_2 = 0 $$ $$I_2 = \frac{I_1\times{R_3} + V_2}{R_2 + R_3}$$ ..... (2) By equating above (1) and (2) we can eliminate $$I_2$$ and hence get the following: $$I_1 = \frac{V_2*R_3 + V_1*(R_2+R_3)}{(R_2+R_3)(R_3+R_1)-R_{3}^{2}}$$ ..... (3)

We end up with the above three equations and now substitute the values given in the above equations and solve the variables. If you feel lost up to this point, do go back to the beginning of the example and try it out again. Think of this as just another mathematical problem requiring solving by use of simultaneous equations with two unknowns!

Notice that we work with variables only and try to solve the equation to its simplest form. Only after arriving at a simplified equation can we then substitute in the values of resistors, voltages and currents. This can save you a lot of trouble because, if you go wrong you can easily trace your work to the problem.

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Part 6 : Example (Continued)
It should be clear that: from (3) $$\begin{matrix}\ I_1 &=& \frac{(7V)*(10\Omega) + (15V)*(15\Omega)}{(15\Omega)*(30\Omega)-(10\Omega)^{2}} \\ \ \\ \ &=& \frac{295}{350} \\ \ \\ \ & = & 0.843A \end{matrix}$$.

Substitute the above result into (2)

$$\begin{matrix}\ I_2 &=& \frac{(7V)+(0.843A\times{10\Omega})}{15\Omega} \\ \ \\ \ &=& \frac{15.43V}{15\Omega} \\ \ \\ \ & = & 1.029A \end{matrix}$$. The positive sign for $$I_2$$ only tells us that Current $$I_2$$ flows in the same direction to our initial assumed direction. Thus now we can calculate Current through $$R_3$$ as follows: $$\begin{matrix}\ I_{R3} &=& (I_1 - I_2) \\ \ \\ \ &=& 0.843A -(1.029A) \\ \ \\ \ & = & -0.186A \end{matrix}$$.

The Negative sign for $$I_{R3}$$ is the result of $$I_1$$ < $$I_2$$, which tells us that Current $$I_2$$ is stronger than $$I_1$$ resulting in $$I_{R3}$$ flowing in the same direction as the stronger Current $$I_2$$.

If you are lost repeat this example and try to follow the logic, otherwise just send a message to the course instructor as outlined in Part 8.

 * }

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Part 7:
The method used to solve the above problem is very tedious, when the complexity of the circuit is increased the method becomes very cumbersome and almost impossible to use in solving circuit equations. This method is used just to illustrate KVL in this lesson. In Lesson 08, a more efficient method of solving these kinds of circuit problems using KVL is introduced in a form of mesh analysis.

Try the following exercise on your own and compare your answers with the given possible solution.

Exercise 5
Consider Figure 5.4 with the following Parameters:
 * $$V_1 = 15V$$
 * $$V_2 = 7V$$
 * $$R_1 = 20\Omega$$
 * $$R_2 = 5\Omega$$
 * $$R_3 = 10\Omega$$

Find current through $$R_3$$ using Kirchhoff's Voltage Law.

 * Answers to Exercise 5

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Part 8:
Further Reading Links:

 * Kirchhoff's circuit laws

References:

 * Nilsson, James W. and Riedel, Susan A. Electric Circuits (5th ed.). Addison-Wesley.  (1996).ISBN 020155707X

Completion list
Once you finish your Exercises you can post your score here! To post your score just e-mail your course co-ordinator your name and score *@undefined.

 * }


text:
Electric Circuit Analysis/Kirchhoff's Current Law

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Lesson Review 5:
What you need to remember from Kirchhoff's Voltage Law. If you ever feel lost, do not be shy to go back to the previous lesson & go through it again. You can learn by repitition.

 * Remember what was learned in Passive sign convention, You can go back and revise Lesson 1.

 * Define Kirchhoff's Voltage Law ( word-by-word ).

 * Kirchhoff's Voltage Law: $$\sum_nv_n = v_4 + v_1 + v_2 + v_3 = 0$$

Lesson 6: Preview
This Lesson is about Kirchhoff's Current Law. The student/User is expected to understand the following at the end of the lesson.

 * Remember what was learned in Passive sign convention, You can go back and revise Lesson 1.

 * Define Kirchhoff's Current Law ( word-by-word ).

 * Kirchhoff's Current Law: $$\sum_ni_n = i_1 + i_2 + i_3 + i_4 = 0$$

 * style="width: 50%; background-color: PaleGreen; border: 1px solid #777777; -moz-border-radius-topleft: 2px; -moz-border-radius-bottomleft: 2px; -moz-border-radius-topright: 2px; -moz-border-radius-bottomright: 2px;" colspan="1"; rowspan="1"|

 * }

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Part 1: Kirchhoff's Current Law
Kirchhoff's Current Law states:

The sum of the currents entering a particular point must be zero.

We can now define the electrical point physically connecting two or more electric circuit components, as a NODE. Note that a positive current leaving a point is considered to be a negative current entering that point.

Mathematically, Kirchhoff's Current Law is given by

$$\sum_ni_n = 0$$

For reference, this law is sometimes called Kirchhoff's first law, Kirchhoff's point rule, Kirchhoff's junction rule, and Kirchhoff's first rule.

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Part 2:Kirchhoff's Current Law (Cont...)
We observe four currents "entering" the junction depicted as the bold black dot in Figure 6.1. Of course, two currents are actually exiting the junction, but for the purposes of circuit analysis it is generally less restrictive to consider what are in actuality positive currents flowing out of a junction to be negative currents flowing into that junction (mathematically the same thing). Doing so allows us to write Kirchhoff's law for this example as:

$$\sum_ni_n = i_1 + i_2 + i_3 + i_4 = 0$$

 * }

{| cellpadding="15" cellspacing="5" style="width: 100%; background-color: inherit; margin-left: auto; margin-right: auto"
 * style="width: 50%; background-color: PaleGreen; border: 1px solid Gray; -moz-border-radius-topleft: 8px; -moz-border-radius-bottomleft: 8px; -moz-border-radius-topright: 8px; -moz-border-radius-bottomright: 8px; height: 60px;" colspan="1" |

Part 3
It may not be clear at this point why we insist on thinking of negative currents flowing into a junction instead of positive currents flowing out. But note that Figure 6.1 provides us with more information that we generally can expect to get when analysing circuits, namely the helpful arrows indicating the direction of current flow. If we don't have such assistance, we generally should not pass judgment on the direction of current flow (i.e., placing a negative sign before our current variable) until we calculate it, lest we confuse ourselves and make mistakes.

Nevertheless in this case we have the extra information of directional arrows in Figure 6.1, so we should take advantage of it. We know that currents i2 and i3 flow into the junction and the currents i1 and i4 flow out. Thus we can write

 * $$i_1 + i_4 = i_2 + i_3$$

Kirchhoff's Current Law as written is only applicable to steady-state current flow (i.e., no alternating current, no signal transmission). It can be extended to include time-dependent current flow, but that is beyond the scope of this section.

Kirchhoff's Current Law is used in a method of circuit analysis referred to as nodal analysis to be discussed in Lecture 7. A node is a section of a circuit where there is no change in voltage (where there are no components, wire is often assumed to be perfectly conductive).

Each node is used to form an equation, and the equations are then solved simultaneously, giving the voltages at each node.

 * style="width: 50%; background-color: PaleGreen; border: 1px solid #777777; -moz-border-radius-topleft: 2px; -moz-border-radius-bottomleft: 2px; -moz-border-radius-topright: 2px; -moz-border-radius-bottomright: 2px;" colspan="1"; rowspan="1"|

Part 4 : Example
Consider Figure 6.2 with the following Parameters:
 * $$V_1 = 15V$$
 * $$V_2 = 7V$$
 * $$R_1 = 20\Omega$$
 * $$R_2 = 5\Omega$$
 * $$R_3 = 10\Omega$$

Find current through $$R_3$$ using Kirchhoff's Current Law. Solution:

This is the same example we solved in Exercise 5.

Figure 6.3 shows Voltages at Nodes a, b, c and d.

We use node a as common node ( ground if you like ). thus $$V_a = 0V$$.

 * }

{| cellpadding="15" cellspacing="5" style="width: 100%; background-color: inherit; margin-left: auto; margin-right: auto"
 * style="width: 50%; background-color: PaleGreen; border: 1px solid Gray; -moz-border-radius-topleft: 8px; -moz-border-radius-bottomleft: 8px; -moz-border-radius-topright: 8px; -moz-border-radius-bottomright: 8px; height: 60px;" colspan="1" |

Part 5 : Example (Continued)
 From Node b we get:
 * $$V_b = -V_1 = -15V $$

From Node d we get:
 * $$V_d = V_2 = 7V $$

It is clear that we must solve Vc, in order to complete Voltage definitions at all nodes. Vc will be found by applying KCL at node c and solving the resulting equations as follows: $$i_1 = i_2 + i_3 $$ $$ \frac{V_b - V_c}{R_1} = \frac{V_c}{R_3} + \frac{V_c - V_d}{R_2}$$

and $$ \frac{V_b}{R_1} - \frac{V_c}{R_1} - \frac{V_c}{R_3} - \frac{V_c}{R_2} + \frac{V_d}{R_2} = 0 $$ We can group the like terms to get the following equation:

$$ V_c\left(\frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3}\right) = \frac{V_b}{R_1} + \frac{V_d}{R_2}$$

 * style="width: 50%; background-color: PaleGreen; border: 1px solid #777777; -moz-border-radius-topleft: 2px; -moz-border-radius-bottomleft: 2px; -moz-border-radius-topright: 2px; -moz-border-radius-bottomright: 2px;" colspan="1"; rowspan="1"|

Part 6 : Example (Continued)
Substitute values into previous equations you get:

$$V_c\left(\frac{1}{20\Omega} + \frac{1}{5\Omega} + \frac{1}{10\Omega}\right) = \frac{-15V}{20\Omega} + \frac{7V}{5\Omega}$$ $$V_c(0.35) = 0.65 $$  thus   $$V_c = 1.857V  $$ Thus now we can calculate Current through $$R_3$$ as follows: $$\begin{matrix}\ I_{R3} &=& \frac{V_c}{R_3} \\ \ \\ \ &=& \frac{1.857}{10} \\ \ \\ \ & = & 0.186A \end{matrix}$$.

Just as we expected! Note that the current here is simplified because we were following voltage definitions and current paths in Figure 6.3.

This method becomes tedious as the complexity of the circuit is increased.

 * }

{| cellpadding="15" cellspacing="5" style="width: 100%; background-color: inherit; margin-left: auto; margin-right: auto"
 * style="width: 50%; background-color: PaleGreen; border: 1px solid Gray; -moz-border-radius-topleft: 8px; -moz-border-radius-bottomleft: 8px; -moz-border-radius-topright: 8px; -moz-border-radius-bottomright: 8px; height: 60px;" colspan="1" |

Part 7:
Further Reading Links:

 * Kirchhoff's circuit laws

References:

 * Nilsson, James W. and Riedel, Susan A. Electric Circuits (5th ed.). Addison-Wesley.  (1996).ISBN 020155707X

Exercise 6
Consider Figure 6.4 with the following Parameters:
 * $$V_1 = 15V$$
 * $$V_2 = 7V$$
 * $$R_1 = 20\Omega$$
 * $$R_2 = 5\Omega$$
 * $$R_3 = 10\Omega$$

Find current through $$R_3$$ using Kirchhoff's Current Law.

 * Answers to Exercise 6

 * style="width: 50%; background-color: PaleGreen; border: 1px solid #777777; -moz-border-radius-topleft: 2px; -moz-border-radius-bottomleft: 2px; -moz-border-radius-topright: 2px; -moz-border-radius-bottomright: 2px;" colspan="1"; rowspan="1"|

Part 8: Completion List
Once you finish your Exercises you can post your score here! To post your score just e-mail your course co-ordinator your name and score *@undefined.

 * }


text:
Template talk:Scholarly ethics

See: Scholarly ethics

title: Template talk:Scholarly ethics


text:
Category:Ethical scholars

See: Scholarly ethics

title: Category:Ethical scholars


text:
Information geometry

Resources

 * Information Geometry: Near Randomness and Near Independence
 * Applications of information geometry to interest rate theory

Further readings

 * Information geometry

title: Information geometry


text:
Category:Categories with portals

This category contains all of the largest categories that have an associated portal. These major portals should be listed at Browse.

title: Category:Categories with portals


text: User:Michael~enwikiversity/Play page

title: User:Michael~enwikiversity/Play page


text:
User talk:TimNelson

Trevor MacInnis 03:24, 23 August 2006 (UTC)

bring some stuff across
"If you point me at some instructions, and ensure I have the necessary privs, I'll bring some stuff across" <-- Thanks for lending a hand! The actual "bring some stuff across" does not take much time and I can continue to do that. Most of the work can be done by anyone. For example, look at the steps I went through for School:Classics fom 12:25 to 12:45. I am still not done; see the instructions at the bottom of this page: Import. If you would like to help with this kind of work (everything except the actual page imports), let me know and we can make a detailed list of what steps you will help with. --JWSchmidt 12:53, 26 August 2006 (UTC)

 * Thanks for your list of steps, now at Help with the migration of Wikiversity pages from Wikibooks. --JWSchmidt 13:41, 26 August 2006 (UTC)

School:Literature and English Studies
School:Literature and English Studies, Topic:Literary Studies, School:Literature. Can you explain to me how these three pages should be/are related? Could I just change School:Literature and English Studies to a division of School:Literature? --JWSchmidt 06:27, 27 August 2006 (UTC)

NPOV vs. Confessions
I thought with your comments at Multiple points of view, you might like Confessions better than WV:NPOV TimNelson 14:13, 27 August 2006 (UTC)

 * Thanks for heads up. I look forward to discussing NPOV, Confessions, etc. :) Reswik 17:26, 27 August 2006 (UTC)

 * Just pointing out that "Multiple points of view" has been moved to Multiple points of view - but you possibly already knew that! Just explaining the strange "you have messages" sign.. :-) Cormaggio beep 14:12, 14 February 2007 (UTC)

Howdy
Thanks for doing that. I'm actually going to axe the School of Literature and English Studies since it's basically useless now with the Department of Literary Studies. ~ATrivedi

Learning by Doing
"I saw you made some comments regarding Learning by Doing, and that Wikiversity has adopted this model. Since I didn't see anything about it on the Policies page, I came here to discuss it." <-- Some things are more fundamental than what is in the policy pages. In this case, "Learning by Doing" is a slogan that captures the intent of the wikiversity "e-learning model". The Wikiversity e-learning model was developed in response to a requested by the Wikimedia Foundation Board of Trustees and it was included in the approved Wikiversity project proposal.

"At the university I went to, all lessons were one of three types:
 * Lectures: learn by listening to authority/notetaking
 * Tutorials: learn by discussion
 * Practicals: learn by doing

Can I suggest that we have the same setup here at Wikiversity?" <-- At Wikiversity a general term that we can use for educational content is "learning resource". So far, learning resources have been roughly divided into learning projects and learning materials.

It is the goal of some Wikiversity participants to create a vast collection of static learning materials, many of which could be downloaded and used by conventional bricks-and-mortar schools. Wikiversity participants are free to take on this task. This is what went on at Wikibooks for several years with very little to show for it.

In my opinion, what Wikiversity needs is a collection of exciting learning projects that will attract wiki participants. If we can engage Wikipedia participants in projects that they are interested in, then the learning materials will accumulate as a by-product of those projects. Here is a familiar example of how participation in a wiki project leads to the production of learning materials: at Wikipedia, editors participate in a project that aims to create an online encyclopedia. Participants can learn about topics by editing encyclopedia articles. Viewed from the perspective of learning projects, Wikipedia has one type of "learning project": write encyclopedia articles. At Wikibooks, a physiology teacher assigned students to work on the Human Physiology textbook. Wikibooks has one type of "learning project": write textbooks. Useful "learning materials", an encyclopedia and textbooks, can be viewed as the by-products of wiki editing projects.

It is important to remember the origin of Wikipedia. Nupedia was an attempt to have experts create an online encyclopedia. The Nupedia article creation process was too slow. Wikipedia was then created and article production became much more rapid; anyone could participate, not just experts. Similarly, "the wiki way" to produce "lessons" is to engage many wiki participants (including non-experts) in tasks that will eventually lead to the creation of useful learning materials. An important part of attracting non-experts is to make Wikiversity a place where people can engage in activities that are related to their personal interests. Everyone has topics that they would like to know more about, and Wikiversity should be an inviting place that allows people to explore their interests. There are far more "students" than "teachers". Very few "teachers" have time to come to Wikiversity and edit. Wikiversity needs to encourage learners to participate and "students" will play a major role in creating Wikiversity content. Wikiversity should not make students wait while experts create lessons. Experts should create learning projects that students can participate in NOW. Once the students are engaged in the Wikiversity community, some of them will start helping to develop Wikiversity learning materials.

"My intention here is to let people choose whichever method suits them best." <-- People are free to develop learning resources using any approach they want. However, Wikiversity is now in a six-month beta phase during which the project is being evaluated by the Board of Trustees in terms of its ability to make a good start on what was in the approved project proposal. Everyone on the Board knows how wikis function. If the Wikiversity community ignores the approved project proposal and moves away from the approved Wikiversity e-learning model then we risk that the project will fail and be terminated by the Board. So, yes, people can "choose whichever method suits them best", but they should choose wisely. We should not create "policy pages" that encourage people to ignore the explicit guidance that has been provided by the Board of Trustees.

"Possibly we should even have more methods of learning, possibly based on w:Theory of multiple intelligences. Basically, that theory says that different people learn different ways. Ignore the fact that Gardner had to redefine the word "intelligence" to make it mean what he wanted to refer to" <-- We have Education as a starting point. We should also make use of Portal:Education.--JWSchmidt 16:11, 28 August 2006 (UTC)

learning by doing/learning projects
"substitute local insult as preferred" <-- I hope we can all keep a spirit of playfulness as we go along! We are involved in a great adventure: learning how to apply wiki technology to facilitate learning. I have yet to find anyone who thinks they know just how this adventure will turn out. Here is something that was said at the recent Wikimania meeting, "I think we should run small experiments, tests, see what works, what doesn't, and be prepared to be flexible and change, and not be too locked into stone about how things should work." I think the spirit of that statement can be applied to Wikiversity. Wikiversity will have people trying to create conventional courses in conventional ways and I have no problem with that. However, I think there are smart people on the Board of Trustees and they had good reasons for deflecting the Wikiversity community away from an emphasis on courses. Courses are one specialized type of "learning project", one that a wiki community should not place too much emphasis on. The yellow "Where are the courses" notice is just an attempt to get people to think about the true potential of the wiki user interface. We can do so much more with wiki than just conventional courses.

"I didn't really 'get' what Learning Projects were" <-- I think it is fairly easy to conceptualize "learning project", even a course can be thought of as a learning project. What is not so easy is knowing what kinds of learning projects are best suited for a wiki. That is what we must discover. I hope the entire Wikiversity community can apply careful thought and bold experimentation to the task of finding the best ways to use our wiki tools to support learning. I doubt if anyone really has a good grasp of "wiki learning projects". We have to discover the good practices for creating and facilitating wiki learning projects.

"Thanks for your patience." <-- In a way, I have been waiting about 30 years to get to where we are now. The term "patience" takes on great depth of meaning when you have to wait decades for something. A serious problem being faced by the Wikiversity community is the need to un-learn much of our "conventional wisdom" about how education should work. Many members of the Wikiversity community have not been able to see any wisdom in the guidance we have received from the Board about things like de-emphasizing courses. The Board is trying to guide us towards ways to utilize the true power of wiki. I hope it is possible to get most people who are interested in Wikiversity to think in new ways so that we can escape the limitations of our old ways of thought. The "wiki way" is a path to great things if we can stay on that path.--JWSchmidt 05:18, 29 August 2006 (UTC)

Sandbox&section=20060830025621&action=edit
I am going to delete this page, unless you have any objections. I fixed the url on the sandbox, that resulted in Sandbox&section=20060830025621&action=edit being created. Please let me know if you absolutely need this page, and I'm being clueless about this.-- digital  _  me   03:11, 30 August 2006 (UTC)

Comment formatting
I've removed your formatting and advice on how to respond. There's already a standard practice for how comments and replies should be formatted in Mediawiki. Coupled with that is a certain expectation of what talk pages should look like. What's the point of adding a special syntax that people would have to remember? -- sebmol ? 13:06, 30 August 2006 (UTC)

 * I did it because I find the current Mediawiki "standard practise" annoying. Examples:
 * # You want to insert some numbering in your comment, and it ends up looking like this
 * # Some people just leave things in with arrows, so it's difficult to skim and see who's saying what
 * # Every time you start another paragraph/bullet point, you have to put a : at the start. That means that you have to think about Mediawiki syntax, and not what you're typing.  Whereas the style I use, you just insert that thing, and then in the bit where it says "Type your comment here", you can put in any multiline text you want, in standard Mediawiki format, without having to put the : down the side
 * However, I don't want to tell other people how to comment, or annoy them, so I changed my comment template so it says "You could", implying that it's optional to use it yourself, and changed the colorscheme to something a bit more normal.
 * Let me know what you think of the comment below.
 * TimNelson (Talk) 14:07, 30 August 2006 (UTC)

 * While I understand your intention with this box, I still don't support it. If you find the display of talk contributions insufficient, you can change your personal Monobook.css to display it differently. Similarly, if you think this might be benefial for the community as a whole, you can propose changing the project-wide Monobook.css. -- sebmol ? 18:33, 1 September 2006 (UTC)

 * It's mostly not the display I find annoying, it's the input. TimNelson (Talk) 10:05, 4 September 2006 (UTC)

bot request
I suggest that you discuss the bot with User:Sebmol. --JWSchmidt 16:50, 31 August 2006 (UTC)

title: User talk:TimNelson


text:
User talk:Classwarrior~enwikiversity

Trevor MacInnis 03:25, 23 August 2006 (UTC)

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 Classwarrior. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Classwarrior~enwikiversity 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.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:32, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 06:05, 19 April 2015 (UTC)

title: User talk:Classwarrior~enwikiversity


text:
User talk:Justintsmith~enwikiversity

Trevor MacInnis 03:27, 23 August 2006 (UTC)

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 Justintsmith. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Justintsmith~enwikiversity 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.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:40, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 06:12, 19 April 2015 (UTC)

title: User talk:Justintsmith~enwikiversity


text:
User talk:Electroguy

Trevor MacInnis 03:27, 23 August 2006 (UTC)

title: User talk:Electroguy


text:
User talk:Kiara481~enwikiversity

Trevor MacInnis 03:27, 23 August 2006 (UTC)

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 Kiara481. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Kiara481~enwikiversity 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.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:41, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 06:13, 19 April 2015 (UTC)

title: User talk:Kiara481~enwikiversity


text:
User talk:Linnferguson

Trevor MacInnis 03:27, 23 August 2006 (UTC)

title: User talk:Linnferguson


text:
User talk:Interiot

Trevor MacInnis 03:27, 23 August 2006 (UTC)

title: User talk:Interiot


text:
User talk:Infinity~enwikiversity

Trevor MacInnis 03:28, 23 August 2006 (UTC)

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 Infinity. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Infinity~enwikiversity 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.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:34, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 06:11, 19 April 2015 (UTC)

title: User talk:Infinity~enwikiversity


text:
User talk:Bukowski 90210~enwikiversity

Trevor MacInnis 03:28, 23 August 2006 (UTC)

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 Bukowski 90210. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Bukowski 90210~enwikiversity 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.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:32, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 06:04, 19 April 2015 (UTC)

title: User talk:Bukowski 90210~enwikiversity


text:
Screensaver Project

Welcome to the screensaver project, an effort to expand the reach and popularity of distributed computing projects. Wikiversity research is all about letting normal users such as yourself participate in and learn from scholarly research. Don't know what protein folding is? Don't know what gravitational waves are? You can still help in researching them! More appropriately, your computer's screensaver can!

What is Distributed computing?
Distributed computing is decentralized and parallel computing, using two or more computers communicating over a network to accomplish a common objective or task. Think Seti@Home, only with other research projects.

How can I help?
Pick a distributed computing project from the list below that interests you, download it, install it, and let your computer run constantly. When the screensaver turns on, the software will begin to process data, periodically returning results and getting more instructions from the project's main server.

If you wish join the wikiversity.org team at the project of your choice. Create one if there is not one already. It will be excellent advertising for us with exactly the highly motivated and some highly educated people who might be interested in wikiversity. It will also help us form a nucleus of users and possibly developers who can put together a distributed grid computing solution when we decide we need one to support Wikiversity's servers or scientific research or learning labs.

List of Distributed computing projects

 * Folding@home - performs simulations of protein folding and other molecular dynamics for disease research
 * Rosetta@home - dedicated to protein structure prediction for disease research
 * SETI@home - analyses radio signals in an attempt to find extraterrestrial life
 * Einstein@home - searches for gravitational waves and other astronomical phenomenon
 * World Community Grid - umbrella for a variety of projects

Please see also Wikiversity Distributed Virtual Supercomputer
 * Wikipedia's List of Distributed Computing Projects

Other types of distributed projects

 * herbaria@home  This is apparently not a distributed computing project but is interesting as a potentential prototype for distributed manual projects that might be suitable for Wikiversity teams.

Note
Though it is a Wikiversity research page, all projects are offsite and not affiliated with Wikiversity. This is considered secondary research. The scope of this page is to inform and better coordinate efforts, such as the establishment of offsite teams and promotion. External links can be added to bad sites, though this is normally caught and reversed before any harm is done. Be forewarned.

title: Screensaver Project


text:
Category:User en-N

These users are native speakers of English.

title: Category:User en-N


text:
User talk:Katxo~enwikiversity

Trevor MacInnis 03:51, 23 August 2006 (UTC)

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 Katxo. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Katxo~enwikiversity 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.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:41, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 06:13, 19 April 2015 (UTC)

title: User talk:Katxo~enwikiversity


text: Portal:Professions

title: Portal:Professions


text:
User talk:Thebabu

Trevor MacInnis 03:51, 23 August 2006 (UTC)

title: User talk:Thebabu


text:
User talk:Abyjohnaby

Trevor MacInnis 03:51, 23 August 2006 (UTC)

title: User talk:Abyjohnaby


text:
User talk:Sebbot

Trevor MacInnis 03:52, 23 August 2006 (UTC)
 * A bot I am. Not sign my posts I do. Thankful for welcome I am. Sebbot 08:39, 5 October 2006 (UTC)

bot inactivity
Hello, we've noticed that the bot that you operate has been inactive since 2006. The bot flag has been temporarily removed for inactivity per changes in the Bots policy. The flag will restored if we notice that the bot has resumed productive activity, or if you request restoration from a bureaucrat. The community does not consider it a big deal to re-grant this right to a trusted contributor. Thank you for the bot contributions that you have made in the past, and we hope that you will consider becoming active again. --mikeu talk 17:16, 23 January 2016 (UTC)

title: User talk:Sebbot


text:
User talk:Yunjuroh

Trevor MacInnis 03:52, 23 August 2006 (UTC)

title: User talk:Yunjuroh


text: User:Trevor MacInnis/CURRENTMINUTEOFDAY

title: User:Trevor MacInnis/CURRENTMINUTEOFDAY


text:
Category:Chemistry

is a top-level Science Library of Congress Classification and Wikiversity category.

title: Category:Chemistry


text:
Test and Quiz

See also: Quiz Welcome to the test and quiz department, for all Wikiversity's test and quiz needs. The page will eventually teach you how to write quizzes and tests for wikiversity and when and where to use them.

Current functionality
Wikiversity is still producing Test and Quiz functionality. Currently available is what are known as a Self-Quizzes, Flashcards, and Handout tests.

Quiz
The wikiversity's Quiz extension allows you to create a quiz with a simplified syntax.

{ this is a question } + this is a right answer -this is a wrong answer

Self-Quizzes
Self Quizzes are quizzes that can be placed on a lesson page or a separate page. They are not graded in the sense that users may answer as many times as they like and no question affects any other question. The answers are hidden from view until the "expand" button above the answer is clicked.

When to use
Self Quizzes can be used as examples in lesson plans, such as in Ohm's Law, or as stand alone quizzes to test knowledge of a chapter of a book, such as College Algebra/GrammarQuiz. When writing a question, make sure that the answer is not obvious. The best questions are the ones that make the test-taker think about what they have learnt. You should consider the difficulty of a question before adding it to a quiz. If a question is too easy, you should examine whether or not it is really necessary, or consider posing a more difficult question.

Usage
Copy and paste the template into the page where the quiz should be made available. Don't forget to delete the spaces before the pipes. There will be multiple types of quizes: two answer, three answer, four answer, or five answer. Presently only the type with four answers works, pending research into a multi-answer system.

This template will give you:

Note that choices are automatically bold, but the answers are not. The number of questions can be increased to 5 by using the template ABCDE, and the answers can be randomly placed by using the template ABCDR. Both work the same as ABCD.

Math questions
d Math questions have special functionality. Functions can be evaluated by using. produces:. Random numbers can be produced by using the current second (which is currently ). This produces a random number from 0 to 59. However, the random number will stay the same until the page is purged from the user's computer memory. Also, only one random number can be generated that way. can be used, but it doesn't change as quickly.

Picture Questions
For the more visual oriented, a picture may be included in a self quiz, such as the template used in the Biology department.

That produces:

Flashcards
When studying a large amount of simple concepts or questions, users and editors might not want all the information to appear at the same time. In the future, large databases of facts and concepts will be stored on Wikiversity. In order to test a sampling of knowledge, a system known as "Flashcards" has been created.

Usage
The flashcard system has many levels. Inorder to make a card around the flash card, the entire system can had a div header like:

Remember to close the box at the end with a  tag. The rest of the system is a very large switch statement, written as

This code produced:

To produce the random number, the expression is used. For other than three cards, change the number 3 to the number of cards needed.

The Calculation
The expression is based on the Parser Functions. performs the calculation. returns the number of seconds since January 1, 1970. mod is the modulo operator, which performs integer division and returns the remainder.

The effect is that this expression takes a big number that changes every second, divides by the number of cards in the flashcard switch statement, and gets the remainder. It then adds 1 so that the result is one-based rather than zero-based.

For example, if the number of cards is 3, the remainder from the calculation will be 0, 1, or 2, no matter how many seconds have elapsed since 1970. Adding 1 returns a value of 1, 2, or 3. This value is then passed to the switch statement to selec

Purge/Get new card
Since mediawiki heavily caches pages to lighten load (stores a copy of the page without reloading it), to get a new card, the stored copy must first be purged. This also is needed on random math questions. A link such as: Get new card is needed.

Another Approach
Flashcards may also be produced using the template. This template is more flexible in that it is a bare  that can be styled to meet the needs of the page design rather than the limitations of the NavFrame class. For example:

Click on the card text to see the answer.

Handout tests
For the purpose of having a graded test, tests can be created via a template, and the answers can be added in later by the test maker. The "students" can take the tests by editing the template, and the grades can be collected by looking at the history of the page that the template was placed on at the time the answers were edited in by the "teacher". Note that there still is no way that looking at other people's tests can be prevented at this time. This encourages collaberative test taking. "Teachers" should be reminded that these tests are not to facilitate a pass/fail type mentality. These types of tests are meant to allow for critical thought as opposed to randomly clicking through the answers as is possible with the self quizes.

To create a template test, enter Template:Nameoftest in the search function, and create the test in the new page. Test makers can start off with the sample code found on the sameple test: Template:Sampletest Note the active part of the code is contained in the include only tags. This code can be substitutide into the students talk page, or a subpage thereof as

Which will produce

Note that in practice the template can be substituted without the answers, with a ? instead of B and D. The instructions can be altered by editing the line beginging with instructions, and the questions can be edited just like with the self quiz.

Timer
The timer can be set and reset for the test, to let test takers know when the answers will be edited into the test. The current code shows which corrisponds to a month long test starting on 11/2. To reset the timer to another start day, change the month from 11 to the current month and the day from 2 to the current day. Simmilar schemes can be done for day long or year long tests. Note the current formulation of the timer does not function properly when the new year is within the month of the test. To shorten the test length, edit the first 31 to the number of days that the test should go.

Answers
When the time has run out, edit the subpages of the your test, and they will be automatically included in the test takers pages. Note that once the test is over, the template can be reused, though the history of the previous test will be stored, so do not use the exact questions.

Things to do

 * Look into multi-question templates
 * Look into adding buttons like the multilingual on on beta
 * Look into finding or making a standard random number generator
 * Bug meta devs into making a gradable version
 * Use random number generator to make a flashcard system for mirwin's java cards.
 * Make a random test generator

The testing grounds
For testing new ideas -->Test and Quiz sandbox

Participants

 * Rayc 19:51, 11 November 2006 (UTC)
 * McCormack 17:49, 29 March 2007 (UTC)
 * Lrbabe 13:53, 10 May 2007 (UTC)
 * CQ 20:57, 24 May 2007 (UTC)
 * (Add name here)

Open source software

 * The quiz extension of the wikiversity
 * QuizJava
 * jMemorize
 * jFlash

Specifications
IMS Question and Test Interoperability Assessment Test, Section, and Item Information Model

title: Test and Quiz


text:
Template talk:Userpage

The template currently reads: "This is not an encyclopedia article" [Empahsis added]. Is "encyclopedia article" the best phrase for this project? Reuvenk 04:16, 23 August 2006 (UTC)

title: Template talk:Userpage


text:
User talk:Reuvenk

--HappyCamper 04:29, 23 August 2006 (UTC)

title: User talk:Reuvenk


text:
Portal:Engineering/Discussions

Portal for Engineering Discussions

This is a place for pickup discussions regarding engineering. Question and answer, imagineering, requirements analysis, specific technical problems,etc. Any discussion related to engineering is appropriate and since this page is FDL'ed may easily be ported into appropriate lessons or other places in the Wikiversity Engineering databases.

Perhaps we can generate some interest in establishing a distributed supercomputer system for Wikiversity's future projects. When not busy with our priority stuff it could help with others routine work as proposed here: http://en.wikiversity.org/wiki/Screensaver_Project

Design Study in Progress, All Participants are Welcome
An industrial supplierLunar_Boom_Town/LOX_Domestic_and_Exports at Lunar Boom Town needs some top level design studies undertaken to allow effective business planning to proceed. Ideally several options will be articulated according to various engineering criteria established. Output quantity planning is not yet complete and may require engineers and planners to articulate several different approaches according to anticipated economies of scale, market demand, operating efficiencies, etc. Mirwin 19:44, 25 September 2007 (UTC)

Discussion topics/ideas

 * How can engineering be utilized to benefit humanity?
 * What are examples of engineering projects that have benefited humanity?
 * How can one best start and initiate a massive project that will benefit humanity?
 * How can engineering be utilized to reduce the negative effects of global warming?

title: Portal:Engineering/Discussions


text:
User talk:RobertLutz

HappyCamper 04:58, 23 August 2006 (UTC)

Screensaver Project
Thanks for those links at Screensaver Project. One of the things I would really like for Wikiversity would be a system for tracking which pages at Wikiversity get the most page views. Second, I am told that the database for the "search" function only updates once a week' I do not understand the technical limitations, but I am told that it puts too much burden on Wikimedia servers to keep track of page hits. I think there is a similar argument for not doing daily updates of the database that is used for the "search function". Do you think it would be possible to set up some kind of "@home" that would use personal computers to aid Wikiversity? Besides possibly helping track Wikiversity page use and more frequent updates of the database that is used for searches inside Wikiversity, another possible "at home" project would relate to developing learning resources. There is a lot of interest in possibly using computer-generated videos as a major type of learning resource that would be developed by Wikiversity participants working in all topic areas. Maybe there could be a "wikiversity@home" project that would make personal computer CPU cycles available for a queue of movie-rendering jobs being done by Wikiversity participants. What do you think? --JWSchmidt 13:08, 27 August 2006 (UTC)

You're very welcome for the screensave links. And thank you for the project idea. I'm really enthusiastic about this form of distributed computing. It's a really clever use of computing resources that would otherwise be sitting around idle. And clearly there are lots of worthy causes that require a great deal of computational power. I'd love to help out as much as I can, but right now I'm pretty far down the learning curve when it comes to networking and internet protocols. I suppose that goes for a lot of the people who are involved or will get involved with Wikiversity projects. If you could give me an idea of what is needed, I will see what I can do. --Robert 17:21, 28 August 2006 (UTC)

title: User talk:RobertLutz


text:
Talk:Calculus/Real Numbers and Their Development

Placeholder for content I will upload later today. Content will motivate the use of the real number system, what a mathematician means by continuity, and introduce the concept of the limit as it pertains to sequences and series. Ron 05:03, 23 August 2006 (UTC)

 * Okay, we'll stay tuned :-) --HappyCamper 05:06, 23 August 2006 (UTC)

Imaginary numbers
I know this is about real analysis, but would it be worthwhile to mention something about the imaginary numbers? --HappyCamper 00:34, 24 August 2006 (UTC)

 * Hmm. Complex numbers are pretty complex to motivate at this elementary point. :D Nevertheless, I'll see if I can work them into the end of this lesson, because they are extremely important in completing our concept of number. -- Ron 01:03, 24 August 2006 (UTC)

 * Don't forget about quaternions, and octernions. Ooh...and sprinkle some stuff about groups...ah! The beauty of mathematics!

 * Seriously, I read the article. Quite nicely written I might add. I'm tempted to dig up my notes on pi and e, and perhaps add them here as well. Would be interesting tidbits I think. --HappyCamper 02:55, 24 August 2006 (UTC)


text:
Wikiversity:Colloquium/archives

2024

 * /December 2024/
 * /November 2024/
 * /October 2024/
 * /September 2024/
 * /August 2024/
 * /July 2024/
 * /June 2024/
 * /May 2024/
 * /April 2024/
 * /March 2024/
 * /February 2024/
 * /January 2024/

2023

 * /December 2023/
 * /November 2023/
 * /October 2023/
 * /September 2023/
 * /August 2023/
 * /July 2023/
 * /June 2023/
 * /May 2023/
 * /April 2023/
 * /March 2023/
 * /February 2023/
 * /January 2023/

2022

 * /December 2022/
 * /November 2022/
 * /October 2022/
 * /September 2022/
 * /August 2022/
 * /July 2022/
 * /June 2022/
 * /May 2022/
 * /April 2022/
 * /March 2022/
 * /February 2022/
 * /January 2022/

2021

 * /December 2021/
 * /November 2021/
 * /October 2021/
 * /September 2021/
 * /August 2021/
 * /July 2021/
 * /June 2021/
 * /May 2021/
 * /April 2021/
 * /March 2021/
 * /February 2021/
 * /January 2021/

2020

 * /December 2020/
 * /November 2020/
 * /October 2020/
 * /September 2020/
 * /August 2020/
 * /July 2020/
 * /June 2020/
 * /May 2020/
 * /April 2020/
 * /March 2020/
 * /February 2020/
 * /January 2020/

2019

 * /December 2019/
 * /November 2019/
 * /October 2019/
 * /September 2019/
 * /August 2019/
 * /July 2019/
 * /June 2019/
 * /May 2019/
 * /April 2019/
 * /March 2019/
 * /February 2019/
 * /January 2019/

2018

 * /December 2018/
 * /November 2018/
 * /October 2018/
 * /September 2018/
 * /August 2018/
 * /July 2018/
 * /June 2018/
 * /May 2018/
 * /April 2018/
 * /March 2018/
 * /February 2018/
 * /January 2018/

2017

 * /December 2017/
 * /November 2017/
 * /October 2017/
 * /September 2017/
 * /August 2017/
 * /July 2017/
 * /June 2017/
 * /May 2017/
 * /April 2017/
 * /March 2017/
 * /February 2017/
 * /January 2017/

2016

 * /December 2016/
 * /November 2016/
 * /October 2016/
 * /September 2016/
 * /August 2016/
 * /July 2016/
 * /June 2016/
 * /May 2016/
 * /April 2016/
 * /March 2016/
 * /February 2016/
 * /January 2016/

2015

 * December 2015
 * November 2015
 * October 2015
 * September 2015
 * August 2015
 * July 2015
 * June 2015
 * May 2015
 * April 2015
 * March 2015
 * February 2015
 * January 2015

2014

 * December 2014
 * November 2014
 * October 2014
 * September 2014
 * August 2014
 * July 2014
 * June 2014
 * May 2014
 * April 2014
 * March 2014
 * February 2014
 * January 2014

2013

 * December 2013
 * November 2013
 * October 2013
 * September 2013
 * August 2013
 * July 2013
 * June 2013
 * May 2013
 * April 2013
 * March 2013
 * February 2013
 * January 2013

2012

 * December 2012
 * November 2012
 * October 2012
 * September 2012
 * August 2012
 * July 2012
 * June 2012
 * May 2012
 * April 2012
 * March 2012
 * February 2012
 * January 2012

2011

 * December 2011
 * November 2011
 * October 2011
 * September 2011
 * August 2011
 * July 2011
 * June 2011
 * May 2011
 * April 2011
 * March 2011
 * February 2011
 * January 2011

2010

 * December 2010
 * November 2010
 * October 2010
 * September 2010
 * August 2010
 * July 2010
 * June 2010
 * May 2010
 * April 2010
 * March 2010
 * February 2010
 * January 2010

2009

 * December 2009
 * November 2009
 * October 2009
 * September 2009
 * August 2009
 * July 2009
 * June 2009
 * May 2009
 * April 2009
 * March 2009
 * February 2009
 * January 2009

2008

 * December 2008
 * November 2008
 * October 2008
 * September 2008
 * August 2008
 * July 2008
 * June 2008
 * May 2008
 * April 2008
 * March 2008
 * February 2008
 * January 2008

2007

 * December 2007
 * November 2007
 * October 2007
 * September 2007
 * August 2007
 * July 2007
 * June 2007
 * May 2007
 * April 2007
 * March 2007
 * February 2007
 * January 2007

2006

 * December 2006
 * November 2006
 * October 2006
 * September 2006
 * August 2006

title: Wikiversity:Colloquium/archives