sin, cos, tan and rounding error

Question

I\'m doing some trigonometry calculations in C/C++ and am running into problems with rounding errors. For example, on my Linux system:

#include 

        

Answer 1

Maybe too low accuracy of implementation

M_PI = 3.14159265358979323846 (20 digits)

http://fresh2refresh.com/c/c-function/c-math-h-library-functions/