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Annotation of researchv9/libc/math/asin.c, revision 1.1

1.1     ! root        1: /*
        !             2:        asin(arg) and acos(arg) return the arcsin, arccos,
        !             3:        respectively of their arguments.
        !             4: 
        !             5:        Arctan is called after appropriate range reduction.
        !             6: */
        !             7: 
        !             8: #include       <errno.h>
        !             9: int errno;
        !            10: double atan();
        !            11: double sqrt();
        !            12: static double pio2     = 1.570796326794896619;
        !            13: 
        !            14: double
        !            15: asin(arg) double arg; {
        !            16: 
        !            17:        double sign, temp;
        !            18: 
        !            19:        sign = 1.;
        !            20:        if(arg <0){
        !            21:                arg = -arg;
        !            22:                sign = -1.;
        !            23:        }
        !            24: 
        !            25:        if(arg > 1.){
        !            26:                errno = EDOM;
        !            27:                return(0.);
        !            28:        }
        !            29: 
        !            30:        temp = sqrt(1. - arg*arg);
        !            31:        if(arg > 0.7)
        !            32:                temp = pio2 - atan(temp/arg);
        !            33:        else
        !            34:                temp = atan(arg/temp);
        !            35: 
        !            36:        return(sign*temp);
        !            37: }
        !            38: 
        !            39: double
        !            40: acos(arg) double arg; {
        !            41: 
        !            42:        if((arg > 1.) || (arg < -1.)){
        !            43:                errno = EDOM;
        !            44:                return(0.);
        !            45:        }
        !            46: 
        !            47:        return(pio2 - asin(arg));
        !            48: }

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