— Function: int gsl_sf_sin_err_e (double x, double dx, gsl_sf_result * result)

This routine computes the sine of an angle x with an associated absolute error dx, \sin(x \pm dx). Note that this function is provided in the error-handling form only since its purpose is to compute the propagated error.

— Function: int gsl_sf_cos_err_e (double x, double dx, gsl_sf_result * result)

This routine computes the cosine of an angle x with an associated absolute error dx, \cos(x \pm dx). Note that this function is provided in the error-handling form only since its purpose is to compute the propagated error.