Homework 10

Here is the exam you took today.

Your homework, due Mon 14 April at 5pm, is to solve the two problems you did not attempt on the exam.

Exam II is imminent

After finishing proofreading the exam and making a formula sheet, I quickly took the exam myself. Solving the exam, fixing typos/errors, and checking that the formula sheet had everything you needed took me 32 minutes.

I expect you can do the exam in an hour if you don't need to use the formula sheet, since you only have to do 75% of the problems, and don't have to proofread per se ...

I think you are well prepared for the exam. Read all the problems first, and choose your 6 wisely. Solve the ones you really know the best first, and work your way down. Time management is crucial, so don't get stuck anywhere - carefully read all the problems first, it will save you time in the end. There will be heavy partial credit, like on the homework, so show all your work - demonstrating you know what you are doing even with a numerically wrong answer is worth a lot of points.

And, for the night owls (or early risers I suppose), your formula sheet is here. You're better off reading homework solutions at this late hour though.

HW 9 solutions

So far I only have solutions for the first two problems. Over the next hours I will be updating the solutions ... hopefully all or most of them will be posted by 10pm.

Here is what I have so far. Check it every hour or so starting at 8pm ... I'll update this post when they are complete.

Exam-wise: study the quiz and homework solutions, and you will be fine.
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UPDATE 10pm: rough solutions are finished for 1-3, 7-9. I have to finish writing the exam now, so problems 4-6 will have to wait until at least 11:30 ...

Office Hours Monday, misc.

I'll be in my office from 11-2 on Monday for exam-related questions ...

Also, this is interesting ... a lawsuit claiming that students' notes infringe on the professor's copyright. I will not comment directly, there is subtlety involved in this case ...

For the record, my notes are under an open content license. Basically, you can distribute them in whole or in part in any medium you like, without changes. That is, libre, not merely gratis, or free as in "free speech," not "free beer." If you modify the notes, or want to make them into a book, you do need my permission. I doubt you'll break the bank selling them, since they are free online though ...

Tangentially related anecdote follows, with little relation to ph102 ...

I published my Ph.D. thesis under a similar license. I had written several chapters which I though were a good review of my field at the time, and though the best thing would be to make it freely available to anyone who could use it. At the time I felt very strongly that information should be free whenever possible, without creating real or artificial barriers for those who genuinely want to learn something. If your hard work can benefit someone else, that is reason enough to do it. I still feel that way, and that is why nearly everything we do in ph102 is online, for free. When I get to it, anyway.

In my thesis (and in the notes, for that matter), I even carefully remade every figure myself to avoid using any copyrighted material whatsoever- since I had such a hard time finding figures I could freely use, why not save someone else the trouble down the road. It can be tough to find nice explanatory figures for basic things that aren't the Intellectual Property of someone or another. My aim was subversion: if I have to make my own figures anyway, give them away for free, so no one else has to go through the trouble. "Information wants to be free," so the saying goes.

So, a few months after my Ph.D. or so, I was in a conference listening to a talk, and about three slides in was one of my figures in the introduction. Six months later or so, a colleague asked me to help him write a review article. Guess where a good number of the figures came from! This was some years ago, so and things have become outdated a bit, but still every now and again at a conference, I do a double-take, and realize I'm looking at my own pictures ...

That is probably the most satisfying feeling I've had as a scientist thusfar. And that is the idea behind the notes. You're already paying to listen to me - and paying well - there is no reason you should pay a second time, or pay to share what you've learned when you leave here.

On that note, I still have quite some editing to do ...

* Paper and ink still costs money of course. Hats off the the SUPe store, who did a brilliant job, and went out of their way to keep your cost at a bare minimum.
** This post is obviously my own viewpoint, and not that of UA. Disclaimer applies.

Homework 8 solutions

At long last, the homework 8 solutions are out. Homework 9 solutions and additional problems on lenses are forthcoming ...

Also, since you are dying to know: below is the breakdown of scores by question for the last two homework sets. Click for a larger image.

Preemptiveness

Thursday, there will be no lab. Before you become unreasonably distraught, let me explain our alternative plan.

The plan is the following: we finish the lenses material and solve some problems for the first 45 minutes. What we have left is basically to pull together all of the arcane geometry we have used so far and put it into practice - as you did in the lab yesterday. I wasn't joking, we really have done all the math we need for every lens problem you will encounter, the rest is just artwork. Thus, a lot of the first half of class will involve practical examples rather than geometrical proofs.

And then, during the second half of class, there is the preemptiveness. The second half of the class will be entirely devoted to exam II review. Come ready with any and all questions, and I will attempt to answer them for about an hour.

If you don't come with questions, I will invent my own and answer those ... which is usually far less interesting from your point of view.

Office hours for Wed 2 April

I have double booked myself a little bit tomorrow ... I have a short meeting from 11:00-11:30, but will be available from 11:30 onward tomorrow for homework questions.