Java Code to evaluate the cos(x) without using math function

Problem:

Design an algorithm to evaluate the cos(x) as defined by the infinite series expansion

Cos(x) = 1 - x2/2! + x4/4! - x6/6! + ..........

Solution:

package com.myprograms;

import java.util.Scanner;


public class CosFunction {

public static void main(String[] args) {
Scanner s = new Scanner(System.in);
System.out.println("enter radious value");
double x = s.nextDouble();
double sum  = 1.0;

for(int i=2,j=1; i<20; i = i+2,j++){
sum += Math.pow(-1, j) * Math.pow(x, i) / findFactorial(i);
}
        System.out.println(sum);
s.close();

}

public static int findFactorial(int n){
int product = 1;
for(int i=1; i<= n; i++){
product = product * i;
}
return product;
}

}

Output:

enter radious value
1.047
0.5001710767161183