C in a Nutshell

Name

cacosh

Synopsis

Calculates the inverse hyperbolic cosine of a complex number

#include <complex.h>
double complexcacosh( double complex z );
float complex cacoshf( float complex z );
long double complex cacoshl( long double complex z );

The cacosh() functions return the complex number whose hyperbolic cosine is equal to the argument z. The real part of the return value is non-negative; the imaginary part is in the interval [-πi, +πi].

Example

double complex v, z ;
double a = 0.0, b = 0.0;

puts("Calculate the inverse hyperbolic cosine of a complex number,"
     " cacosh(z)\n");
puts("Enter the real and imaginary parts of a complex number:");
if ( scanf("%lf %lf", &a, &b) == 2)
{
  z = a + b * I;
  printf( "z = %.2f %+.2f*I.\n", creal(z), cimag(z) );

  v =cacosh(z);
  printf( "The cacosh(z) function yields %.2f %+.2f*I.\n",
          creal(v), cimag(v) );
  printf( "The inverse function, ccosh(cacosh(z)), yields %.2f %+.2f*I.\n",
          creal( ccosh(v)), cimag( ccosh(v)) );
}
else
  printf("Invalid input.\n");

See Also

Other hyperbolic trigonometry functions for complex numbers: casinh(), catanh(), csinh(), ccosh(), and ctanh(); the hyperbolic cosine and inverse hyperbolic cosine functions for real numbers: cosh() and acosh()