Homework 5, due October 8, 2014.

[goodwine]

Reading: Chapter 4.

Exercises: 4.3, 4.4, 4.6, 4.7, 4.9, 4.12, 4.14 and 4.15.

In 4.6, you do not have to write a computer program, i.e., ignore the sentence starting with "Demonstrate whether..."

[ksmith44]

I am having a bit of a difficulty with the phase angle plot for 4.3. I am getting a jump after the ratio = 1, and unwrap() is not working. How can I correct that?

[goodwine]

I am having a bit of a difficulty with the phase angle plot for 4.3. I am getting a jump after the ratio = 1, and unwrap() is not working. How can I correct that?

If the answer is basically right, but only shifted by pi or something, then you don't have to fix it. A couple things that might help are atan2(), plotting it in sections and adding or subtracting pi in the part that needs to be shifted. Again, though, if it's right, but just looks bad, it's not required for you to get the plot to be pretty.

[ksmith44]

Using atan2() fixed it! Thanks.

[mmulvihill]

Could somebody please explain how to properly use atan2()? I'm very confused on what I need to do in order to properly use the function because I do not understand what it does.

[goodwine]

Could somebody please explain how to properly use atan2()? I'm very confused on what I need to do in order to properly use the function because I do not understand what it does.

It is able to determine which quadrant the inverse tangent function is because it keeps track of the sign of x and y: http://www.mathworks.com/help/matlab/re ... #buct8h0-4

In other words, it can distinguish atan((-x)/(-y)) and atan(x/y), but regular atan() cannot.