ref: ba13c3d3919814b33af1faa50a5d0e8f5dc139a7
dir: /sys/src/libc/port/tanh.c/
#include <u.h> #include <libc.h> /* tanh(arg) computes the hyperbolic tangent of its floating point argument. sinh and cosh are called except for large arguments, which would cause overflow improperly. */ double tanh(double arg) { if(arg < 0) { arg = -arg; if(arg > 21) return -1; return -sinh(arg)/cosh(arg); } if(arg > 21) return 1; return sinh(arg)/cosh(arg); }