C acos() function

C acos() function - Calculate arccosine

The acos() function is used to calculate the arccosine of a given number, expressed in radians, in the range 0 to pi.

Syntax:

double acos(double x)

Parameters:

Return value from acos()

• Upon successful completion, the function return the arc cosine of x.
• The value of x must be between -1 and 1 inclusive.

Example: acos() function

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

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
 
#define MAX  1.0
#define MIN -1.0
 
int main(void)
{
  double x, y; 
  printf("Input the value of x: ");
  scanf( "%lf", &x );
  y = acos(x);
  if (x > MAX)
    printf( "Error: %lf not in the range!\n", x );
  else if (x < MIN)
    printf( "Error: %lf not in the range!\n", x );
  else 
    printf("acos(%lf) = %lf\n", x, y);
} 

Output:

Input the value of x: 1
acos(1.000000) = 0.000000

Input the value of x: 1.5
Error: 1.500000 not in the range!

Input the value of x: -1.5
Error: -1.500000 not in the range!

C Programming Code Editor:

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