Thats quite cute. I imagine it is (doing something equivalent to) using the complex exponential and taking the real an imaginary parts? exp(iz) = cos(z) + i sin

Thats quite cute. I imagine it is (doing something equivalent to) using the complex exponential and taking the real an imaginary parts? exp(iz) = cos(z) + i sin(z), so by working out exp you can get cos and sin for free.