Reading: All of Chapter 5. More details than usual were left for the reading for this assignment, so it is more important than usual to do the reading this week.
Exercises: 5.75.10, 5.16 and 5.19.
Homework 7, due October 27, 2011.

 Site Admin
 Posts: 1596
 Joined: Tue Aug 24, 2004 4:54 pm
 Location: 376 Fitzpatrick
 Contact:
Homework 7, due October 27, 2011.
Bill Goodwine, 376 Fitzpatrick
Re: Homework 7, due October 27, 2011.
The Airy Eqn is written differently in question 5.7 than what ch.5.5.1 provides. So I am guessing that we should solve for the eqn given in the problem?
5.9 gives:
d2y /dx2 (x)+xy(x) = 0.
While Ch, 5.51 gives:
d2y/dx2 (x)−xy(x) = 0
5.9 gives:
d2y /dx2 (x)+xy(x) = 0.
While Ch, 5.51 gives:
d2y/dx2 (x)−xy(x) = 0
Re: Homework 7, due October 27, 2011.
For question 5.16, the equation uses dy/dt but then is multiplied by x. I am confused as to what to do with 3 variables because we are assuming a solution that only involves y and x. In example 5.7 in the book you substitute dy/dx for dy/dt. Is this acceptable?

 Site Admin
 Posts: 1596
 Joined: Tue Aug 24, 2004 4:54 pm
 Location: 376 Fitzpatrick
 Contact:
Re: Homework 7, due October 27, 2011.
Do it the way that is stated in the problem. They are just different forms of the Airy Equation.Hopz wrote:The Airy Eqn is written differently in question 5.7 than what ch.5.5.1 provides. So I am guessing that we should solve for the eqn given in the problem?
5.9 gives:
d2y /dx2 (x)+xy(x) = 0.
While Ch, 5.51 gives:
d2y/dx2 (x)−xy(x) = 0
Bill Goodwine, 376 Fitzpatrick

 Site Admin
 Posts: 1596
 Joined: Tue Aug 24, 2004 4:54 pm
 Location: 376 Fitzpatrick
 Contact:
Re: Homework 7, due October 27, 2011.
That's a big typo. The independent variable is x, so both derivative terms should be with respect to x.jconcelm wrote:For question 5.16, the equation uses dy/dt but then is multiplied by x. I am confused as to what to do with 3 variables because we are assuming a solution that only involves y and x. In example 5.7 in the book you substitute dy/dx for dy/dt. Is this acceptable?
Bill Goodwine, 376 Fitzpatrick
Re: Homework 7, due October 27, 2011.
for problem 5.19 I am confused on how to get the value for a0. Do we need initial conditions?

 Site Admin
 Posts: 1596
 Joined: Tue Aug 24, 2004 4:54 pm
 Location: 376 Fitzpatrick
 Contact:
Re: Homework 7, due October 27, 2011.
You can just leave it in terms of a0 and a1.Jessie wrote:for problem 5.19 I am confused on how to get the value for a0. Do we need initial conditions?
Bill Goodwine, 376 Fitzpatrick