acos() and acosf()

  #include <math.h>
  

  double acos (double x);

  

  float  acosf (float x);

  

acos() computes the principal value of the arc cosine of x.

The arc cosine cos^(-1)(x) of x in the range between 0 and Pi, if x is in the range -1 <= x <= 1. If x is not in this range, the function returns NAN and sets errno to EDOM.

asin() and asinf()

atan() and atanf()

atan2() and atan2f()

cos() and cosf()

sin() and sinf()

tan() and tanf()