## cosh

Hiperbolic cosine by tau approximation for rtau object.

Hiperbolic cosine by tau approximation for rtau object.

f = cosh(r)

F = cosh(r) is a function to approximate by tau method cosh(r), r in [a, b]. We are using schursolver function, which will decide the approximation degree to achieve 1e-16.

r = rigth member in tau method (rtau object).

f = coefficients of cosh(r).

sin, sinh, cos, exp and log.