This C Program calculates the sum of cos(x) series.

Here is source code of the C program to C Program calculates the sum of cos(x) series. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

`/*`

`* C program to find the sum of cos(x) series`

`*/`

`#include <stdio.h>`

`#include <math.h>`

void main()

`{`

int n, x1, i, j;

float x, sign, cosx, fact;

printf("Enter the number of the terms in a series\n");

scanf("%d", &n);

printf("Enter the value of x(in degrees)\n");

scanf("%f", &x);

x1 = x;

`/* Degrees to radians */`

x = x * (3.142 / 180.0);

cosx = 1;

sign = -1;

for (i = 2; i <= n; i = i + 2)

`{`

fact = 1;

for (j = 1; j <= i; j++)

`{`

fact = fact * j;

`}`

cosx = cosx + (pow(x, i) / fact) * sign;

sign = sign * (-1);

`}`

printf("Sum of the cosine series = %7.2f\n", cosx);

printf("The value of cos(%d) using library function = %f\n", x1,

cos(x));

`}`

$ cc pgm63.c -lm $ a.out Enter the number of the terms in a series 3 Enter the value of x(in degrees) 90 Sum of the cosine series = -0.23 The value of cos(90) using library function = -0.000204

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