# 2nd order linear differential equation

• Jan 16th 2011, 07:23 AM
TwoPlusTwo
2nd order linear differential equation
Hi, can anyone tell me why this is wrong?

First I factor the characteristic equation and get that r is either 0 or -1:
Attachment 20458

Then I plug those values into the solution for two real roots:

Attachment 20459

But according to wolfram the second term is supposed to be negative. Why is that?
• Jan 16th 2011, 07:38 AM
Random Variable
Because Wolfram Alpha is stupid? Since $C_{2}$ can be positive or negative, it can absorb the negative.
• Jan 16th 2011, 07:52 AM
TwoPlusTwo
Haha! That makes sense. Thanks