C Programming Code Examples C > Mathematics Code Examples C Program to Calculate the Value of cos(x) C Program to Calculate the Value of cos(x) /* - C program to find the value of cos(x) using the series - up to the given accuracy (without using user defined function) - also print cos(x) using library function. */ #include <stdio.h> #include <math.h> #include <stdlib.h> void main() { int j, x1; float accuracy, term, denominator, x, cosx, cosval; printf("Enter the value of x (in degrees) \n"); scanf("%f", &x); x1 = x; /* Converting degrees to radians */ x = x * (3.142 / 180.0); cosval = cos(x); printf("Enter the accuracy for the result \n"); scanf("%f", &accuracy); term = 1; cosx = term; j = 1; do { denominator = 2 * j * (2 * j - 1); term = -term * x * x / denominator; cosx = cosx + term; j = j + 1; } while (accuracy <= fabs(cosval - cosx)); printf("Sum of the cosine series = %f\n", cosx); printf("Using Library function cos(%d) = %f\n", x1, cos(x)); }