atan2 in c

What is atan2 in c programming?

atan2 in c is used to find arc tangent in radians of y/x based on signs of both values that determine the correct quadrant.

It is defined in math.h header file.

Prototype

double atan2(double y, double x);

Parameter

This function takes two floating point values as x and y co-ordinate values.

Return value

This function returns arc tangent of y/x ,in the interval [-pi,+pi] radians.


Example program for atan2 in c

#include<stdio.h>
#include<math.h>
#define PI 3.14
int main()
{
  double x=4.0,y=5.0,res,val;
  val=180.0/PI;
  res=atan2(y,x)*val;
  printf("The arc tangent value is %lf \n",res);
  return 0;
}
Example program for atan2 in c
Output for example program for atan2 in c

While using gcc use below command to add math header.

gcc file_name.c -lm

Code explanation

atan2 function is called by passing x and y values to it. The result is multiplied to get the arc tangent value in radians. The result is printed onto the console.

atan2() Man page


Difference between atan2 and atan in c

atan2 in c is used to find arc tangent in radians of y/x based on signs of both values that determine the correct quadrant. atan in c is a mathematical function that is used to find the arc tangent value of a given number in radians.

atan2 takes two input parameters as x and y co-ordinates. atan takes one input parameter.

Prototypes are as follows

double atan2(double y, double x);

double atan(double y);
atan2( )atan( )
Used to find arc tangent in radians of y/x based on signs of both values.Used to find arc tangent of a given number.
double atan2(double y, double x);double atan(double y);

People also ask for

What is the difference between atan2 and tan in c?

atan2 in c is used to find arc tangent in radians of y/x based on signs of both values that determine the correct quadrant. tan in c is a mathematical function that is used to find the tangent of a given number.

What is the difference between atan2 and tanh in c?

atan2 in c is used to find arc tangent in radians of y/x based on signs of both values that determine the correct quadrant. tanh in c is used to find the hyperbolic tangent of a given number.