src/complex/transcendental/cl_C_tan.cc

   1 // tan().
   2
   3 // General includes.
   4 #include "cl_sysdep.h"
   5
   6 // Specification.
   7 #include "cl_complex.h"
   8
   9
  10 // Implementation.
  11
  12 #include "cl_C.h"
  13 #include "cl_real.h"
  14
  15 const cl_N tan (const cl_N& x)
  16 {
  17 // Methode:
  18 // x reell -> (/ (sin x) (cos x))
  19 // x = a+bi -> (/ (complex (* (sin a) (cosh b)) (* (cos a) (sinh b)))
  20 //                (complex (* (cos a) (cosh b)) (- (* (sin a) (sinh b)))) )
  21         if (realp(x)) {
  22                 DeclareType(cl_R,x);
  23                 var cl_cos_sin_t trig = cl_cos_sin(x);
  24                 return trig.sin / trig.cos;
  25         } else {
  26                 DeclareType(cl_C,x);
  27                 // x=a+bi
  28                 var const cl_R& a = realpart(x);
  29                 var const cl_R& b = imagpart(x);
  30                 var cl_cosh_sinh_t hyp_b = cl_cosh_sinh(b); // cosh(b), sinh(b) errechnen
  31                 var cl_cos_sin_t trig_a = cl_cos_sin(a); // cos(a), sin(a) errechnen
  32                 return
  33                         complex_C(trig_a.sin * hyp_b.cosh, // sin(a)*cosh(b)
  34                                   trig_a.cos * hyp_b.sinh // cos(a)*sinh(b), nicht Fixnum 0
  35                                  )
  36                       / complex(trig_a.cos * hyp_b.cosh, // cos(a)*cosh(b)
  37                                 - (trig_a.sin * hyp_b.sinh) // -sin(a)*sinh(b)
  38                                );
  39         }
  40 }