So this is going to be 1 1 2, this 1 1 2 right over here. The antiderivative of this is e to the negative x squared, and then of course I might have some other constant. I'll just call that c two. And once again, if this part over here, what I just did seems strange, the u substitution, you might want to review that piece. Now, what can I do here? Well I have a constant on the left-hand side, it's an arbitrary constant, we don't know what it is. I haven't used this initial condition yet, we could call it.