Diff. Eq.

I'm at a loss about how to solve the following differential equation:

x'' = x^0.25

That is, double derivative of x equals x to the 0.25th power.

It's very frustrating because I have a feeling it's very trivial. Can anybody help, please? Thanks.

Alright, I'll provide a solution for some cases I know how to solve so you can at least see what this is about.

   x''+x=0
General solution: c1*sin(t)+c2*cos(t), with c1,c2 arbitrary constants

   x''+x'=0
General solution: c1+c2*exp(-t), with c1,c2 arbitrary constants, exp() exponential function