www.pudn.com > CRGAB.zip > SINX.C

/* 
HEADER:		; 
TITLE:          Sin(x) series approximation; 
VERSION:	1.0; 
 
DESCRIPTION:    Function to demonstrate how a Taylor series expansion of 
		sin(x) may be implemented.  Convergence is fast and 
		arguments are accepted in degrees.  Large arguments accepted.; 
 
KEYWORDS:       Sin(x), math functions, approximations; 
SYSTEM:		MSDOS 1.x, 2.x, 3.x; 
FILENAME:	SINX; 
WARNINGS:       None ; 
 
SEE-ALSO:	LNX, EXP, IFAC, ABS_VAL,MATHCLUD.FUN; 
AUTHORS:	Dr. Ronald J. Terry; 
COMPILERS:	Turbo C 2.0; 
*/ 
 
#include "mathclud.fun" 
 
double sinx(double sinarg) 
{ 
     double sum=0.0,s1=100.0,xval,radtodeg=3.14159265358979/180; 
     int k=0,oddeven=1; 
     sinarg = ((sinarg/360)-(int)(sinarg/360))*360.0; /*  convert to  */ 
     sinarg = sinarg*radtodeg;           /*  radians and scale input  */ 
     for(;;) 
     { 
       sum = sum + oddeven*Intpwr(sinarg,2*k+1)/Ifac(2*k+1); 
       oddeven = oddeven*(-1); 
       k++;                            		    /* sum series */ 
       if(Abs_val(s1-sum)<=1e-10) 
	 break; 
       s1 = sum; 
     } 
     return (sum); 
}