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Homework 3, due September 19, 2007.
Posted: Wed Sep 12, 2007 10:57 am
by goodwine
Reading assignment: Chapter 1, section 1.8 and chapter 3.
Homework assignment: problems 3.1, 3.4, 3.8, 3.9, 3.11, 3.12 (if necessary, refer to the electronic pdf version of the course text for clearer graphs) and 3.14 from the
course text.
In addition, write a computer program that uses Euler's method to determine an approximate numerical solution to the initial value problem in Problem 3.1. Submit a listing of your computer code as well as a plot of the solution. You may use FORTRAN, C, or C++, but not Matlab to determine the solution. You may use Matlab to plot the solution. If you would prefer to use an alternative programming language, you must receive permission from the instructor.
mistake
Posted: Tue Sep 18, 2007 11:18 am
by scox7
In section 3.4.2, page 74. Just under equation 3.16 there is u1(t) and u2(t), but there's no integral for u2(t). It's the same in the following equations for x particular and the final answer. There should be an integral there correct?
Re: mistake
Posted: Tue Sep 18, 2007 2:20 pm
by goodwine
scox7 wrote:In section 3.4.2, page 74. Just under equation 3.16 there is u1(t) and u2(t), but there's no integral for u2(t). It's the same in the following equations for x particular and the final answer. There should be an integral there correct?
Yes, you are correct.
fortran syntax
Posted: Thu Sep 20, 2007 12:06 pm
by Luke Nakatsukasa
is this the syntax for e^2
exp**2
Re: fortran syntax
Posted: Thu Sep 20, 2007 12:50 pm
by goodwine
Luke Nakatsukasa wrote:is this the syntax for e^2
exp**2
No, I think it should be
Posted: Thu Sep 20, 2007 12:54 pm
by goodwine
i thoght i should write in the do loop.. something along the lines of
x(1) = x(1) + x(2) dt
x(2) = x(2) + x(3) dt
x(3) = t**2 + 3*exp**t - 4*x(1) ! from problem 3.1
where am i going wrong?
A second order equation is equivalent to two first order equations, so there should only be an x(1) and x(2). If you do it the way I was last night, the derivative of x(1) is x(2) and the derivative of x(2) is determined from solving the original second order equation for d^2x/dt^2.
Also, if that's copied directly out of your code, you are missing an * for times in the first two equations.
mistake
Posted: Thu Sep 20, 2007 2:28 pm
by scox7
For Problem 3.12, the graphs in both of the tables (Table 3.2, Table 3.3 p 80-81) do not have graphs plotted for "plot 2". What should we do as far as matching those graphs?
Re: mistake
Posted: Thu Sep 20, 2007 4:10 pm
by goodwine
scox7 wrote:For Problem 3.12, the graphs in both of the tables (Table 3.2, Table 3.3 p 80-81) do not have graphs plotted for "plot 2". What should we do as far as matching those graphs?
That's due to poor photocopying, I assume. Check the
electronic version where you can zoom in/out as much as you want.
error in text
Posted: Thu Sep 20, 2007 4:32 pm
by lhaas
page 64, the third equation in example 3.3.1:
there should be a 6 next to the last term
3.12
Posted: Thu Sep 20, 2007 5:09 pm
by scox7
The electronic version looks the same. The line for "plot 2" in the legends appears to be white. Either way, the plots do not appear.
Re: 3.12
Posted: Thu Sep 20, 2007 5:53 pm
by goodwine
scox7 wrote:The electronic version looks the same. The line for "plot 2" in the legends appears to be white. Either way, the plots do not appear.
They appear just fine in mine. I guess you need to ask someone, or if all else fails, stop by my office tomorrow morning.