casin.c raw

   1  #include "complex_impl.h"
   2  
   3  // FIXME
   4  
   5  /* asin(z) = -i log(i z + sqrt(1 - z*z)) */
   6  
   7  double complex casin(double complex z)
   8  {
   9  	double complex w;
  10  	double x, y;
  11  
  12  	x = creal(z);
  13  	y = cimag(z);
  14  	w = CMPLX(1.0 - (x - y)*(x + y), -2.0*x*y);
  15  	double complex r = clog(CMPLX(-y, x) + csqrt(w));
  16  	return CMPLX(cimag(r), -creal(r));
  17  }
  18