cosh
double cosh(double);
inline float cosh(float __X) { return __coshf(__X); }
inline long double cosh(long double __X) { return __coshl(__X); }
extern double cosh(double);
using std::cosh;
c = cosh((double)x);
D_RE(ans) = C * cosh(x);
D_IM(ans) = S * cosh(x);