C 言語によるプログラミングは習っているはずだし、 フリーの処理系もあるので、本当はこれくらい自力で出来て欲しいところ。
/*
* computesin.c
*/
#include <stdio.h>
#include <math.h>
double halfsin(double cosx)
{
return sqrt((1-cosx)/2);
}
double halfcos(double cosx)
{
return sqrt((1+cosx)/2);
}
int main()
{
double root2, root3, root5;
double sin18, cos18, sin15, cos15, sin3, cos3, sin1p5, cos1p5;
double sin0p75, cos0p75;
root2 = sqrt(2.0);
root3 = sqrt(3.0);
root5 = sqrt(5.0);
sin18 = (root5-1)/4;
cos18 = sqrt((5+root5)/2)/2;
sin15 = (root3 - 1)/(2*root2);
cos15 = (root3 + 1)/(2*root2);
sin3 = sin18*cos15-cos18*sin15;
cos3 = cos18*cos15+sin18*sin15;
sin1p5 = halfsin(cos3);
cos1p5 = halfcos(cos3);
sin0p75 = halfsin(cos1p5);
cos0p75 = halfcos(cos1p5);
printf("sin18 =%20.15f\n", sin18);
printf("cos18 =%20.15f\n", cos18);
printf("sin15 =%20.15f\n", sin15);
printf("cos15 =%20.15f\n", cos15);
printf("sin3 =%20.15f\n", sin3);
printf("cos3 =%20.15f\n", cos3);
printf("sin1.5 =%20.15f\n", sin1p5);
printf("cos1.5 =%20.15f\n", cos1p5);
printf("sin0.75=%20.15f\n", sin0p75);
printf("cos0.75=%20.15f\n", cos0p75);
return 0;
}
oyabun% ./computesin sin18 = 0.309016994374947 cos18 = 0.951056516295154 sin15 = 0.258819045102521 cos15 = 0.965925826289068 sin3 = 0.052335956242944 cos3 = 0.998629534754574 sin1.5 = 0.026176948307874 cos1.5 = 0.999657324975557 sin0.75= 0.013089595571345 cos0.75= 0.999914327574007 oyabun% |
Solaris では long double の精度が高いので、それを利用すると
oyabun% ./computesin-long sin18 = 0.30901699437494742410229341718281908 cos18 = 0.95105651629515357211643933337938214 sin15 = 0.25881904510252076234889883762404831 cos15 = 0.96592582628906828674974319972889726 sin3 = 0.05233595624294383272211862960907841 cos3 = 0.99862953475457387378449205843943650 sin1.5 = 0.02617694830787315261061168555411346 cos1.5 = 0.99965732497555728003676088836767982 sin0.75= 0.01308959557134444019028420970285323 cos0.75= 0.99991432757400703224892204745488401 oyabun% |