The atan() function defined in the math.h header file. It helps to return the arc tangent value of the given number in radians.
double atan(double x); #where x should be a double
The atan() function takes a single parameter in the range of any value from negative to positive. Using cast operator we can explicitly convert the type to double to find the atan() of type int, float, or long double.
Parameter | Description | Required / Optional |
---|---|---|
double value | Any double value from negative to positive | Required |
The return value of atan() function is in the range of [-pi/2,+pi/2] in radians.
Input | Return Value |
---|---|
x = [-1, +1] | [-pi/2,+pi/2] in radians |
-1 > x or x > 1 | NaN (not a number) |
#include <stdio.h>
#include <math.h>
#define PI 3.141592654
int main()
{
double n = 1.0;
double output;
output = atan(n);
printf("The Inverse of tan(%.2f) is equal to %.2f in radians", n, output);
// Converting radians to degrees
output = (output * 180) / PI;
printf("\nThe Inverse of tan(%.2f) is equal to %.2f in degrees", n, output);
return 0;
}
Output:
The Inverse of tan(1.00) is equal to 0.79 in radians The Inverse of tan(1.00) is equal to 45 in degrees
#include <stdio.h>
#include <math.h>
int main () {
double v, out, value;
v = 1.0;
value = 180.0 / PI;
out = atan (v) * value;
printf("The arc tangent of %lf is %lf degrees", v, out);
return(0);
}
Output:
The arc tangent of 1.000000 is 45.000000 degrees