- #1
Rumpelstiltzkin
- 17
- 0
Here's the problem:
Solve [tex]ty'' + 2y' + ty = 0[/tex]
with [tex]lim_{t\rightarrow0+} y = 0[/tex]
and
[tex] y(\pi) = 0[/tex]
So here's my working:
[tex]-\frac{d}{ds}[s^2Y - sy(0) - y'(0)] + 2[sY - y(0)] - Y' = 0[/tex]
[tex]-[2sY + s^2Y' - s] + 2[sY - y(0)] - Y' = 0[/tex]
Arranging terms, I get:
[tex] Y' = \frac{s-2y(0)}{s^2+1}[/tex]
and
[tex]-Y' = \frac{2y(0)-s}{s^2+1}[/tex]
[tex]L^{-1}(-Y')= L^{-1}(\frac{2y(0)}{s^2+1}) - L^{-1}(\frac{s}{s^2+1})[/tex]
[tex]ty = 2y(0)sint - cost[/tex]
[tex] y = \frac{2y(0)sint}{t} - \frac{cost}{t}[/tex]
The answer is [tex]y = \frac{sint}{t}[/tex]
What's wrong?
Thanks..
Solve [tex]ty'' + 2y' + ty = 0[/tex]
with [tex]lim_{t\rightarrow0+} y = 0[/tex]
and
[tex] y(\pi) = 0[/tex]
So here's my working:
[tex]-\frac{d}{ds}[s^2Y - sy(0) - y'(0)] + 2[sY - y(0)] - Y' = 0[/tex]
[tex]-[2sY + s^2Y' - s] + 2[sY - y(0)] - Y' = 0[/tex]
Arranging terms, I get:
[tex] Y' = \frac{s-2y(0)}{s^2+1}[/tex]
and
[tex]-Y' = \frac{2y(0)-s}{s^2+1}[/tex]
[tex]L^{-1}(-Y')= L^{-1}(\frac{2y(0)}{s^2+1}) - L^{-1}(\frac{s}{s^2+1})[/tex]
[tex]ty = 2y(0)sint - cost[/tex]
[tex] y = \frac{2y(0)sint}{t} - \frac{cost}{t}[/tex]
The answer is [tex]y = \frac{sint}{t}[/tex]
What's wrong?
Thanks..
Last edited: