Originally Posted by

**mistykz** So the question is:

Using the existence and uniqueness theorem, show that the differential equation dy/dt = sqrt(y-1), with initial condition that y(0)=2, has a unique solution. Furthermore, solve it.

I verified that it both existed and was unique, and I also got a solution but I'm not quite sure if it's right...

I separated it into 1/sqrt(y-1) * dy = 1 dt

integrated: 2 sqrt(y-1) = t + C (**)

divide by 2: sqrt(y-1) = t/2 + C

now this is where I'm not sure if I messed up or not. Silly, since it's simple algebra, but when i remove the square root from the y-1, would the right side turn into (t^2)/4 + C, or (t^2)/4 + Ct + C? I chose the former and got a final answer of y(t) = (t^2)/4 + 2

I'm totally braindead right now, haha, but should I have done it the second way?