atan2&sin

//弧度转化角度：弧度*180/PI
//角度转化弧度：角度*PI/180

#include <math.h>
#include <stdio.h>
const double PI=acos(-1.0);
//sin传入的参数的是弧度
void main()
{
    int z=;
    double   x   =   10.0,   y   =   10.0;
    double   result;
    //sin30结果
    printf("sin(%d)=%.2lf\n",z,sin(*PI*z/360.0));
    result=atan2(y,   x);     //结果返回是弧度
    printf("The   arc   tangent   ratio   of   %lf   is   %.1lf\n",   (y   /   x),   result*/PI);
    //sin45的结果
    printf("sin(%.0f)=%.2lf\n",result*/PI,sin(result));    //注意不要用%d
}