Library Function atan2 in Math Class

Library Function atan2 of math.h Header File in C

On this page we will discuss about library function atan2 in math class which is used in C.
The C header file math.h contains the standard math library functions that can be used for performing various mathematical operations. The atan2 function returns the arc tangent of \frac{y}{x} in radians.
Library Function atan2 in Math Class

Library Function atan2 in Math class used in C

In C programming language the atan2 function is included in math.h header file.

The range of input arguments which are passed to atan2 function can be either a positive or a negative number and returns the arc tangent of parameter \frac{y}{x} in radians.

Declaration of atan2 function

double atan2(double y, double x);

Parameters of atan2 function

The atan2 function accepts two input arguments of double type as given below:

ParameterDescription
x axisThis parameter is represented by x coordinate at input point of type double.
y axisThis parameter is represented by y coordinate at input point of type double.

Return value of atan2 function

The atan2  function returns a value in radians and it’s type is double. The function return value lies in the range of \left [ -\Pi,\Pi \right ] radians.

ParameterReturn Value
x> 0,y> 0\; or\; x<0,y< 0 It returns the value between -\Pi\; and\; \Pi of type double.
x=0, y=0The function will return a domain error.

Implementation of Library Function math.h atan2

Example 1:

The following code shows the use of atan2 function.
Run
#include <stdio.h>
#include <math.h>
#define PI 3.141592654

int main()
{
    double number = 3.0;
    double return_value;

    return_value = atan(number);

    printf("Inverse of tan(%.2f) function = %.2f in radians", number, return_value);

    // Converting radians to degrees
    return_value = (return_value * 180) / PI;
    printf("\nInverse of tan(%.2f) function = %.2f in degrees", number, return_value);

    return 0;
}

Output:

The arc tangent of -12.5 and 4.6 is 160.0 degrees.

Example 2:

The following code shows use of atan2 function when inputs are entered by user.
Run
#include <stdio.h>
#include <math.h>
#define PI 3.141592654

int main()
{
   /* Define temporary variables */
  double variable1, variable2, result;
  
  /* Assign the two values to variables to find the atan2 of */
  printf("Enter the value of variable1: ");
  scanf("%lf", &variable1);
  printf("Enter the value of variable2: ");
  scanf("%lf", &variable2);

  /* Calculate the Arc Tangent of value1 and value2 */
  result = atan2(variable2, variable1);
  
  /* Converting radians to degrees */
  result = result * 180.0/PI;

  /* Display the result of the calculation */
  printf("The arc tangent of %.1lf and %.1lf is %.1lf degrees.", variable1, variable2, result);
  return 0;
}

Output:

Enter the value of variable1: 6.78
Enter the value of variable2: -13.5
The arc tangent of 6.8 and -13.5 is -63.3 degrees.

Prime Course Trailer

Related Banners

Get PrepInsta Prime & get Access to all 200+ courses offered by PrepInsta in One Subscription

Get over 200+ course One Subscription

Courses like AI/ML, Cloud Computing, Ethical Hacking, C, C++, Java, Python, DSA (All Languages), Competitive Coding (All Languages), TCS, Infosys, Wipro, Amazon, DBMS, SQL and others

Checkout list of all the video courses in PrepInsta Prime Subscription

Checkout list of all the video courses in PrepInsta Prime Subscription