# Thread: 2nd order linear differential equation

1. ## 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:

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

But according to wolfram the second term is supposed to be negative. Why is that?

2. Because Wolfram Alpha is stupid? Since $C_{2}$ can be positive or negative, it can absorb the negative.

3. Haha! That makes sense. Thanks