C library - ccos() function

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The C complex library ccos() function is commonly known for trigonometric function which operates the complex cosine of a given complex number. This function comes under the header <complex.h>.

Syntax

Following is the C library syntax of the ccos() function −

double complex ccos(double complex z);

Parameters

This function takes only a single parameter(z).

Return Value

It return double complex value when there is no error occurs.

Example 1

Following is the C library program that illustration of ccos() function where we will find the cosine of a constant complex number.

#include <stdio.h>
#include <complex.h>

int main() {
   double complex x = 1 + 2 * I;
   double complex result = ccos(x);

   printf("cos(1 + 2i) = %.3f + %.3fi\n", creal(result), cimag(result));
   return 0;
}

Output

On execution of above code, we get the following result −

cos(1 + 2i) = 2.033 + -3.052i

Example 2

To find the complex of imaginary values it allows ccos() to accept the input value which is purely imaginary. Below is the implementation of following statement.

#include <stdio.h>
#include <complex.h>

int main() {
   double y_values[] = { 1.0, 2.0, 3.0 };
   for (int i = 0; i < 3; ++i) {
       double complex z = I * y_values[i];
       double complex result = ccos(z);
       printf("cos(i%.1f) = %.3f + %.3fi\n", y_values[i], creal(result), cimag(result));
   }
   return 0;
}

Output

After executing the above code, we get the following result −

cos(i1.0) = 1.543 + -0.000i
cos(i2.0) = 3.762 + -0.000i
cos(i3.0) = 10.068 + -0.000i

Example 3

Here, we will create a custom function to operate the task of cosine using a user assigned angle(in radian).

#include <stdio.h>
#include <math.h>
#include <complex.h>

double complex custom_ccos(double angle) {

   // calculation of custom complex cosine
   return ccos(angle);
}

int main() {

   // angle in radian
   double angle = 0.5; 
   double complex res = custom_ccos(angle);

   printf("The result of custom cos(%.3f) = %.3f + %.3fi\n", angle, creal(res), cimag(res));
   return 0;
}

Output

The above code produces the following result −

The result of custom cos(0.500) = 0.878 + -0.000i