C atan() Prototype
double atan(double x);
Function atan() takes a single double argument and returns the value in radians.
The returned value of atan() is of type double.
For a Better Understanding of atan():
[Mathematics] tan-1x = atan(x) [In C programming]
It is defined in <math.h> header file.
C atan() Range
The library function atan() can take any value from negative to positive.
Example: C atan() Function
#include <stdio.h>
#include <math.h>
#define PI 3.141592654
int main() {
double num = 1.0;
double result;
result = atan(num);
printf("Inverse of tan(%.2f) = %.2f in radians", num, result);
// Converting radians to degrees
result = (result * 180) / PI;
printf("\nInverse of tan(%.2f) = %.2f in degrees", num, result);
return 0;
}
Output
Inverse of tan(1.00) = 0.79 in radians Inverse of tan(1.00) = 45.00 in degrees