# Help with a couple differential equation problems.(mostly laplace transforms)

• Dec 10th 2012, 09:42 AM
tmanerchia
Help with a couple differential equation problems.(mostly laplace transforms)

Solve by undetermined coefficients
y'' + 3y = -48x2 * e3x

Find a linear operator that annihilates the given function, and verify
3 + ex * cos2x

Inverse Laplace transforms of
(s + 1)3/s4

0.9s/((s - 0.1)(s + 0.2))

Use the Laplace transform to solve the given initial value problem
y'' + y' = 21/2sin21/2t y(0) = 10, y'(0)= 0

2y''' + 3y'' - 3y' - 2y = e-t y(0)= 0, y'(0)= 0, y''(0)= 1

Evaluate the Laplace transform of
L[(1 - et + 3e-4t)cos5t]

L-1[(2s - 1)/(s2(s2 + 1)3)]

I'm sorry I don't have all of the symbols down yet.

edit: I solved a couple
• Dec 10th 2012, 11:53 AM
topsquark
Re: Help with a couple differential equation problems.(mostly laplace transforms)
Quote:

Originally Posted by tmanerchia

Solve by undetermined coefficients
y'' + 3y = -48x2 * e3x

Find a linear operator that annihilates the given function, and verify
3 + ex * cos2x

Inverse Laplace transforms of
(s + 1)3/s4

0.9s/((s - 0.1)(s + 0.2))

Use the Laplace transform to solve the given initial value problem
y'' + y' = 21/2sin21/2t y(0) = 10, y'(0)= 0

2y''' + 3y'' - 3y' - 2y = e-t y(0)= 0, y'(0)= 0, y''(0)= 1

Evaluate the Laplace transform of
L[(1 - et + 3e-4t)cos5t]

L-1[(2s - 1)/(s2(s2 + 1)3)]

I'm sorry I don't have all of the symbols down yet.

edit: I solved a couple

First do not post anywhere near the number of problems you have. Put them is separate threads. It's too confusing to work with.

Second, you said you have done some work. Please show us what you have done.

-Dan
• Dec 10th 2012, 12:25 PM
tmanerchia
Re: Help with a couple differential equation problems.(mostly laplace transforms)
I took out the ones I did the work on. The problems that are left are the ones I don't know how to solve. Sorry about having them all in one post I just thought it would be easier that way.