C atan() function

C atan() function - Calculate Arctangent


double atan(double x)

The atan() function is used to calculate the arctangent of x.


Name Description Required /Optional
x This is the floating point value. Required

Return value from atan()

  • The atan() function returns a value in the range -π/2 to π/2 radians.

Example: atan() function

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

#include <stdio.h>
#include <math.h>
int main(void)
    double a,c;
     c = 0.45;
     a = atan(c);
    printf("atan( %lf ) = %lf", c, a);
    c = 0;
    a = atan(c);
    printf("\natan( %lf ) = %lf", c, a);

    c = 1;
    a = atan(c);
    printf("\natan( %lf ) = %lf", c, a);


atan( 0.450000 ) = 0.422854
atan( 0.000000 ) = 0.000000
atan( 1.000000 ) = 0.785398

C Programming Code Editor:

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