Bill Goodwine's Courses

Posted: **Mon Nov 17, 2014 11:55 am**

Reading: all of Chapter 11 (11.6 and 11.7 sections extra credit).

Exercises: 11.2 (let m=1, b=0 and k = 9 pi^2), 11.4 (number 4 only), 11.6, 11.9 (number 3 only), 11.11 and 11.12.

Extra credit: 11.17 and 11.19 (40 points each). Also one problem extra credit (10 points) if you thoroughly read and studied sections 6 and 7. Write on your homework paper that you did so. If the attention and effort your directed toward sections 6 and 7 can not be characterized as such, then you may not say you did it for extra credit.

Posted: **Mon Nov 17, 2014 10:26 pm**

I was just working on question 11.4 on the homework, and I had a question about something in the initial conditions. In the problem (11.4 #4), it says that u(x,0) = 0, however it lists the partial derivative du/dt (x,0) instead. When I was looking at eqn 11.33 in the textbook, it makes the clarification that f(x) is meant to be u(x,0). Since u(x,0) = 0 in this question, then Cn = 0, and that makes the entire solution equal to 0? I just want to make sure that I am following the right approach on this question since it seems a little too convenient for the solution to work out to be 0.

Your reasoning is correct; however, that is listed on the errata for the book. The three different cases are supposed to be for u(x,0), not the derivative. http://controls.ame.nd.edu/mediawiki/in ... Chapter_11

Bill Goodwine's Courses

Homework 9, due November 25, 2014.

Homework 9, due November 25, 2014.

Re: Homework 9, due November 25, 2014.