Atan() - C library function Program

Declaration :

double atan(double x)

Explanation :

Purpose	The C library function double atan(double x) returns the arc tangent of x in radians.
Parameters	x ===> This is the floating point value.
Return Value	This function returns the principal arc tangent of x in the interval [-pi/2+pi/2] radians.
Exception

C Program : Example

The following example shows the usage of atan() function.

#include 
#include 
#define PI 3.14159265
int main ()
{
   double x, ret, val;
   x = 1.0;
   val = 180.0 / PI;
   ret = atan (x) * val;
   printf("The arc tangent of %lf is %lf degrees", x, ret);
   return(0);
}