# Differential equations - finding solution

1. Feb 13, 2010

### shinobiazra

Select the correct solution for dy/dx = 1/[(4y)*(x^3)]

a) x^4
b) x^(-1/4)
c) 1/(x^4)
d) x root 4

Choice D means instead of cubic root, to the power 4 root

Plz explain how to do this. I tried separating variables and integrating the choices but it didn't work. Mayb I should differentiate the solutions instead?

2. Feb 13, 2010

### Staff: Mentor

You're making this harder than it needs to be. The problem isn't asking you to find the solution -- just say which of four given functions is a solution.

For each of your four possible answers, take the derivative and see whether it is equal to 1/[(4 times the function)*x^3].

3. Feb 13, 2010

### LCKurtz

None of the answers are correct, so it is no wonder that when you solved it by separation of variables, nothing worked.