asin(p1)
  public
  
    
    
Computes the arc sine of x. Returns -{PI/2} .. {PI/2}.
   
  
    Show source    
    
      static VALUE
math_asin(VALUE obj, VALUE x)
{
    double d0, d;
    Need_Float(x);
    d0 = RFLOAT_VALUE(x);
    /* check for domain error */
    if (d0 < -1.0 || 1.0 < d0) domain_error("asin");
    d = asin(d0);
    return DBL2NUM(d);
}