atan2 - Returns tangent of a/b in C



  #include <math.h>
  #include <stdio.h>

  int main(void)
  {
  
      printf("Atan2 of %f is %f.\n", -0.9, atan2(-0.9,1.0));
    
    return 0;
  }



Output:
Atan2 of -0.900000 is -0.732815.