### Exponential Function

Function: double gsl_sf_exp (double x)
Function: int gsl_sf_exp_e (double x, gsl_sf_result * result)
  These routines provide an exponential function \exp(x) using GSL semantics and error checking.

Function: int gsl_sf_exp_e10_e (double x, gsl_sf_result_e10 * result)
  This function computes the exponential \exp(x) using the `gsl_sf_result_e10` type to return a result with extended range. This function may be useful if the value of \exp(x) would overflow the numeric range of `double`.

Function: double gsl_sf_exp_mult (double x, double y)
Function: int gsl_sf_exp_mult_e (double x, double y, gsl_sf_result * result)
  These routines exponentiate x and multiply by the factor y to return the product y \exp(x).

Function: int gsl_sf_exp_mult_e10_e (const double x, const double y, gsl_sf_result_e10 * result)
  This function computes the product y \exp(x) using the `gsl_sf_result_e10` type to return a result with extended numeric range.