Very simple differential equation

dy/dt = t^3 * y^3

This is supposed to be solved using seperation of variables, but after seperating and integrating both sides, you end up with y^-2 on one side and a negative number on the other side (after you multiply both sides by -2 to begin to solve for y). Solving for y would require rasing each side to the -1/2 power... but you can't take the square root of a negative number. That is where I'm stuck.

Thanks in advance.

edit: here is what I end up with:

y^-2 = -1/2 * t^4