u cos (\theta) + (n x u) sin (\theta)

ucos(theta)+(Nxu)sin(theta)

Rotation by theta: u * cos(theta) + (nxu) * sin(theta)

We can use Rodrigues' rotation formula here: so it should be ucos(theta)+(Nxu)sin(theta) + N (N.u) (1-cos(theta))

Ucos(theta) + (N x u)sin(theta)