Circular and hyperbolic functions differ by rotations
John
The difference between a circular function and a hyperbolic function is a rotation or two. For example, cosh(z) = cos(iz). You can read that as saying that to find the hyperbolic cosine of z, first you rotate z a quarter turn to the left (i.e. multiply by i) and then take the cosine. For another example, […] The post Circular and hyperbolic functions differ by rotations first appeared on John D. Cook .