Arduino - 三角函数
你需要使用三角函数，比如当你计算移动物体的距离或角速度时。Arduino 提供传统的三角函数（sin，cos，tan，asin，acos，atan），Math.h 包含三角函数的原型函数。
三角函数精确语法
double sin(double x); //returns sine of x radians
double cos(double y); //returns cosine of y radians
double tan(double x); //returns the tangent of x radians
double acos(double x); //returns A, the angle corresponding to cos (A) = x
double asin(double x); //returns A, the angle corresponding to sin (A) = x
double atan(double x); //returns A, the angle corresponding to tan (A) = x
例
double sine = sin(2); // approximately 0.90929737091
double cosine = cos(2); // approximately -0.41614685058
double tangent = tan(2); // approximately -2.18503975868