Is this correct so far?

Printable View

- Mar 7th 2011, 10:14 AMdwsmith\varphi^{(4)}-\lambda\varphi=0

Is this correct so far? - Mar 7th 2011, 10:31 AMAckbeet
I wonder if you're switching problems mid-way here? I get the following:

and

- Mar 7th 2011, 10:36 AMdwsmith
- Mar 7th 2011, 10:55 AMAckbeet
Hmm. You're trying to find a fundamental matrix? If so, I'm afraid this problem is out of my league. Maybe Danny could take a look?

- Mar 7th 2011, 11:05 AMdwsmith
- Mar 7th 2011, 03:05 PMJester
Just a comment @dw - your method would work fine if you were given IC's

but you're not. You're given

Some of it works but you're still left with two equations to solve. Adrian's method is much more natural and direct.

Next, dw, with your two equations for C and D, eliminate C and D and get a single equation for or . - Mar 8th 2011, 10:49 AMdwsmith
- Mar 8th 2011, 11:06 AMJester
Yes, in post 5, you have two equations for C and D. Move the D terms to the right side of both equations and then divide the left side and right sides. The C and D terms will cancel. Then simplify.

- Mar 9th 2011, 11:42 AMdwsmith
- Mar 10th 2011, 11:06 AMdwsmith

Is this much correct?

The solution is:

I have been unable to manipulate my solution in order to obtain the books. I am guessing I am wrong, or I am unable to make a slick substitution with an identity. - Mar 16th 2011, 03:29 PMdwsmith

Now, let and looking at the Taylor expansion of cosh and cos because 0 isn't eigenvalue.

Why the book multiplied through by beats me.