# A second ODE problem that bothers me a lot HELP!

1. May 10, 2009

### whatababy

A second ODE problem that bothers me a lot~~ HELP!

The question is like:
Find the function y1 of t which is the solution of:
9y''-36y'-45y=0
with initial conditions y1(0)=1, y'1(0)=0

y1= ?

Find the function y2 of t which is the solution of:
9y''-36y'-45y=0
with initial conditions y2(0)=0, y'2(0)=1

y2= ?

Find the Wronskian W(t)= W(y1.y2)

W(t)=?

The way I tried to achieve the problem is to solve the characteristic equation, which is
9r2-36r-45=0, which gives r1=5 and r2=-1; then I consider y1 and y2 are exp(r1) and exp(r2) respectively. But it seems my answer is wrong.....

2. May 10, 2009

### whatababy

Re: A second ODE problem that bothers me a lot~~ HELP!

never mind, I got it.