#### 7.31.2 Trigonometric Functions for Complex Arguments

Function: int gsl_sf_complex_sin_e (double zr, double zi, gsl_sf_result * szr, gsl_sf_result * szi)

  This function computes the complex sine, \sin(z_r + i z_i) storing the real and imaginary parts in szr, szi.

Function: int gsl_sf_complex_cos_e (double zr, double zi, gsl_sf_result * czr, gsl_sf_result * czi)

  This function computes the complex cosine, \cos(z_r + i z_i) storing the real and imaginary parts in czr, czi.

Function: int gsl_sf_complex_logsin_e (double zr, double zi, gsl_sf_result * lszr, gsl_sf_result * lszi)

  This function computes the logarithm of the complex sine, \log(\sin(z_r + i z_i)) storing the real and imaginary parts in lszr, lszi.