Find a parametrization of the bumpy torus, given as the set of points which have distance 5+2cos(7θ) from the circle <10cos(θ), 10sin(θ), 0>, where θ is the angle occurring in cylindrical and spherical coordinates.
So, I've calculated the distance r from a point to the z-axis as r = (10+(5+2cos(7θ))cos(ϕ). However, I'm having issues translating it back to Cartesian coordinates. Does anyone want to give me a hand here?