## Homework 5, due October 7, 2009.

Due Wednesday, October 7, 2009.
goodwine
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### Homework 5, due October 7, 2009.

From the course text, problems 4.2, 4.6, 4.11 (part 1 only), 4.12, and 4.13.

4.6 has a typo. The frequencies in the two cos() functions should be omega_1 and omega_2.

You may use the ode45() function from Matlab for all the problems that ask you to write a program to determine an approximate numerical solution.
Bill Goodwine, 376 Fitzpatrick
cplagema

### Re: Homework 5, due October 7, 2009.

I have a question about problem 4.2.
It says to "determine an approximate numerical solution," so are we supposed to actually find the equation x(t) by substituting in the given values, or are we just supposed to use Matlab to plot it? Also, are we supposed to find wn, xo and x˙o, since those values are not given?
goodwine
Posts: 1596
Joined: Tue Aug 24, 2004 4:54 pm
Location: 376 Fitzpatrick
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### Re: Homework 5, due October 7, 2009.

cplagema wrote:I have a question about problem 4.2.
It says to "determine an approximate numerical solution," so are we supposed to actually find the equation x(t) by substituting in the given values, or are we just supposed to use Matlab to plot it? Also, are we supposed to find wn, xo and x˙o, since those values are not given?
You are supposed to use ode45() in matlab to solve it.
Bill Goodwine, 376 Fitzpatrick
mkiener

### Re: Homework 5, due October 7, 2009.

For Problem 4.12,

should we consider just the particular solution for x(t) (and therefore xdot(t) )?

Thank you
mkiener

### Re: Homework 5, due October 7, 2009.

Disregard the last post, I just received the email sent regarding problem 4.12
ckrzysk1

### Re: Homework 5, due October 7, 2009.

In problem 4.11, what is the closed-form solution from Problem 4.3 into which we are supposed to substitute the given values?
Apuente

### Re: Homework 5, due October 7, 2009.

For problem 4.12, it says to find the expression in terms of cos(omega*t + phi), and in the book there are two particular solutions - one in that form and one in the form of cos(omega*t + phi(hat) + psi). Which form should we use?
goodwine
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Joined: Tue Aug 24, 2004 4:54 pm
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### Re: Homework 5, due October 7, 2009.

ckrzysk1 wrote:In problem 4.11, what is the closed-form solution from Problem 4.3 into which we are supposed to substitute the given values?
You determined it for last week's homework. I posted solutions for it.
Bill Goodwine, 376 Fitzpatrick
goodwine
Posts: 1596
Joined: Tue Aug 24, 2004 4:54 pm
Location: 376 Fitzpatrick
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### Re: Homework 5, due October 7, 2009.

Apuente wrote:For problem 4.12, it says to find the expression in terms of cos(omega*t + phi), and in the book there are two particular solutions - one in that form and one in the form of cos(omega*t + phi(hat) + psi). Which form should we use?
You can use either one. The extra phase shift term is in there only because we don't know where the bumpy road started. You can ignore it if you want.
Bill Goodwine, 376 Fitzpatrick
jde98

### Re: Homework 5, due October 7, 2009.

For ode45() outputs do you want the tables handed in or just the plots?
goodwine