Homework 5, due October 1, 2010.

[goodwine]

Reading: For the upcoming exam, you are responsible for all the material in Chapters 1 through 4, with the exception of section 1.6.

Exercises: 4.3, 4.4, 4.7, 4.9, 4.10, 4.12, 4.14, 4.19 and 4.22.

[ypan1]

For 4.4, we need to determine the approximations to the steady solutions for the equations. What do you mean by good approximations? I can find out the values for magnification factor and phase shift from the plots made in 4.3. Should I also plot the particular solutions to the equations?

[goodwine]

For 4.4, we need to determine the approximations to the steady solutions for the equations. What do you mean by good approximations? I can find out the values for magnification factor and phase shift from the plots made in 4.3. Should I also plot the particular solutions to the equations?

The point of the problem is to use those plots to find the approximate particular (steady-state) solution. So, the particular solution and the solutions from the plots should be the same.

[sprender]

Can we just eye up the graphs for problem 4.4 to get an approximation or should we use the equations for the magnification factor and the phase shift?

[goodwine]

Can we just eye up the graphs for problem 4.4 to get an approximation or should we use the equations for the magnification factor and the phase shift?

The former -- the point of the problem is to use the graphs.

[mhubbar3]

I'm having trouble graphing my inverse tan function in matlab for question 4.3 part 4

Heres the code I have:

r = linspace(0,5,1000);
z = 0.2;
x = atan((1.-r.^2)/(2.*z.*r));
plot (r,x)

any suggestions?...

[mhubbar3]

...sorry, the problem i'm having is that its only returning a straight horizontal line for the graph...i also tried just doing the one already in the book on page 98 and the same thing was happening for that one as well.

[goodwine]

...sorry, the problem i'm having is that its only returning a straight horizontal line for the graph...i also tried just doing the one already in the book on page 98 and the same thing was happening for that one as well.

I can't see anything wrong, at least initially. If you type 'x' to see what x is, what does it give? A bunch of different numbers, or a constant one? The only possible issue I can see right now is that / maybe should be ./ Also, you don't need .* for the 2 and zeta terms since those are constants.

[goodwine]

...sorry, the problem i'm having is that its only returning a straight horizontal line for the graph...i also tried just doing the one already in the book on page 98 and the same thing was happening for that one as well.

I can't see anything wrong, at least initially. If you type 'x' to see what x is, what does it give? A bunch of different numbers, or a constant one? The only possible issue I can see right now is that / maybe should be ./ Also, you don't need .* for the 2 and zeta terms since those are constants.

Now that I think about it, I'm > 90% sure it's the ./ If that fixes it, it's probably worthwhile to figure out why.

[mhubbar3]

that worked, thanks