# I Solving u_x=(sin(x))*(u) in Fourier space

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1. Jun 20, 2016

### vector_problems

Does anyone know if it is possible to solve an equation of the type
u_x=(sin(x))*(u)
on a periodic domain using the fft.

I have tried methods using convolutions but have had no success

2. Jun 20, 2016

### Staff: Mentor

What does u_x mean in the context of your problem? It could possibly mean the partial derivative of u with respect to x, or it could mean the x-component of a vector u.

Also, what are you trying to solve for?

3. Jun 20, 2016

### vector_problems

sorry, should have been more clear. u_x is the partial derivative of u w.r.t. x and i am trying to solve for u,

du/dx=(sin(x))*(u)

4. Jun 21, 2016

### Staff: Mentor

Is u a function of any variables other than x? If so, your equation is an ordinary differential equation, and one that is separable and easy to solve analytically.

5. Jun 21, 2016

### LAZYANGEL

You have ux=sin(x)*u

Can't you rewrite it as: y'=y*sin(x)? Solve it as ODE and instead of writing the constant, just assume it's a function of the other variables.