Answer:
The solution code is written in Java.
- public class Main {
- public static void main(String[] args) {
- System.out.print("Please enter a number: ");
- Scanner console = new Scanner(System.in);
- int n = console.nextInt();
- calculateSum1(n);
- calculateSum2(n);
- calculateSum3(n);
- calculateSum4(n);
- }
- public static void calculateSum1 (int num){
- int sum1 = 0;
- for(int i=1; i <= num; i++){
- sum1 += i*i*i;
- }
- System.out.println("Sum 1 : " + sum1);
- }
- public static void calculateSum2 (int num){
- int sum2 = num * num * (num + 1) * (num + 1) / 4;
- System.out.println("Sum 2 : " + sum2);
- }
- public static void calculateSum3 (int num){
- int sum3 = 0;
- for(int i=1; i <=num; i++){
- sum3 += i;
- }
- sum3 = sum3 * sum3;
- System.out.println("Sum 3 : " + sum3);
- }
- public static void calculateSum4 (int num){
- int sum4 = (num * (num + 1) * (2*num + 1)) / (4+2);
- System.out.println("Sum 4 : " + sum4);
- }
- }
Explanation:
Firstly we create four different methods that calculate the sum of the first n cubes in different ways (Line 13 - 43).
This is important to understand the concept of operator precedence to work out the different ways of summation.
For example, The operator * and / will always have higher precedence than +.
On another hand, any expression enclosed within the parenthesis will have highest precedence and therefore the value will be evaluated prior to others.
This is also important to understand the expression evaluation will always start from left to right.
Answer: This means that even though we believe the information is coming from a trusted source, it could still contract a virus due to someone else hacking it or the original sending not being aware of the virus.
Explanation: Just because information comes from a trusted/friendly source does not mean the information is clear of potential threats. Viruses are able to hide in information and the sending may not be aware that the virus is hiding in the information.
