expcos.cpp

   1 // Do the exponential cosine function.
   2
   3 #include "stdafx.h"
   4 #include "defs.h"
   5
   6 void
   7 eval_expcos(void)
   8 {
   9         push(cadr(p1));
  10         eval();
  11         expcos();
  12 }
  13
  14 void
  15 expcos(void)
  16 {
  17         save();
  18
  19         p1 = pop();
  20
  21         push(imaginaryunit);
  22         push(p1);
  23         multiply();
  24         exponential();
  25         push_rational(1, 2);
  26         multiply();
  27
  28         push(imaginaryunit);
  29         negate();
  30         push(p1);
  31         multiply();
  32         exponential();
  33         push_rational(1, 2);
  34         multiply();
  35
  36         add();
  37
  38         restore();
  39 }
  40
  41 #if SELFTEST
  42
  43 static char *s[] = {
  44
  45         "expcos(x)",
  46         "1/2*exp(-i*x)+1/2*exp(i*x)",
  47 };
  48
  49 void
  50 test_expcos(void)
  51 {
  52         test(__FILE__, s, sizeof s / sizeof (char *));
  53 }
  54
  55 #endif