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giangnguyen2412/math_operation.c

Created May 16, 2018 09:50
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  1. giangnguyen2412 created this gist May 16, 2018.
    42 changes: 42 additions & 0 deletions math_operation.c
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,42 @@
    #include <stdlib.h>
    #include <stdio.h>
    #include <math.h>

    int compare_float(double f1, double f2)
    {
    double precision = 0.00000000000000000001;
    if ((f1 - precision) < f2)
    {
    return -1;
    }
    else if ((f1 + precision) > f2)
    {
    return 1;
    }
    else
    {
    return 0;
    }
    }

    double cos(double x){
    if( x < 0.0f )
    x = -x;

    if (0 <= compare_float(x,M_PI_M_2))
    {
    do {
    x -= M_PI_M_2;
    }while(0 <= compare_float(x,M_PI_M_2));

    }

    if ((0 <= compare_float(x, M_PI)) && (-1 == compare_float(x, M_PI_M_2)))
    {
    x -= M_PI;
    return ((-1)*(1.0f - (x*x/2.0f)*( 1.0f - (x*x/12.0f) * ( 1.0f - (x*x/30.0f) * (1.0f - (x*x/56.0f )*(1.0f - (x*x/90.0f)*(1.0f - (x*x/132.0f)*(1.0f - (x*x/182.0f)))))))));
    }
    return 1.0f - (x*x/2.0f)*( 1.0f - (x*x/12.0f) * ( 1.0f - (x*x/30.0f) * (1.0f - (x*x/56.0f )*(1.0f - (x*x/90.0f)*(1.0f - (x*x/132.0f)*(1.0f - (x*x/182.0f)))))));
    }

    double sin(double x){return cos(x-M_PI_2);}