# Homework Help: Simple looking 2nD ODE, with 2 sols, 0 and 3, confused on what to do now!

1. Feb 16, 2006

### mr_coffee

Hello everyone, I have time again to do more math so here i am!
I'm confused on what they want me to do here, I found A and B but they arn't pretty and i dind't even think they are right. Here is the problem, it has 2 inital conditions, both y(x) no y'(x) which also confused me.
ind y as a function of t if
y'' - 3y' = 0,
y(0) = 9, y(1) = 7 .
y(t) =

http://img51.imageshack.us/img51/566/lastscan0ei.jpg [Broken]

THanks! any help would be great!

Last edited by a moderator: May 2, 2017
2. Feb 16, 2006

### assyrian_77

There is a mistake in your line $$7=Be^{3t}+A$$. Can you see it?

EDIT: As so emphatically pointed out below, that is your mistake.

Last edited: Feb 16, 2006
3. Feb 16, 2006

### HallsofIvy

A and B are CONSTANTS!! In y(1)= 7, you didn't set t= 1.

4. Feb 16, 2006

### mr_coffee

Ahh thank you everyone, I friggin' got it:
http://cwcsrv11.cwc.psu.edu/webwork2_files/tmp/equations/cf/6cde53ce8c93c51ddfe1e2f50b5e411.png [Broken]

Last edited by a moderator: May 2, 2017