grad (p) = μ(grad^2 )u

This is the Stokes' Equation/Momentum Equation

How would I find the pressure? How would I integrate this equation to do so?

uis given as

u= { U[1- (3a/2r) + (a^3)/(2r^3)]cosθ, -U[1 - (3a/4r) - (a^3)/(4r^3)]sinθ }

which was previously worked out in spherical coordinates.

How would I begin?