reactos/lib/sdk/crt/math/tanh.c

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/* Copyright (C) 1994 DJ Delorie, see COPYING.DJ for details */
#include <math.h>
#ifdef _MSC_VER
#pragma function(tanh)
#endif
/*
* @implemented
*/
double tanh(double x)
{
if (x > 50)
return 1;
else if (x < -50)
return -1;
else
{
const double ebig = exp(x);
const double esmall = 1.0/ebig;
return (ebig - esmall) / (ebig + esmall);
}
}