summation in java using for loops

[java157]

I am trying to make a summation calculator for the following equation:



Where i is the lower limit (in this case it will always be 0) and n is the upper limit (in this problem the user will be asked to enter an integer value of the upper limit).

Here is my code (so far):

import java.io.*;
public class summation
{
public static void main(String args[]) throws IOException
{

BufferedReader keybd = new BufferedReader(new InputStreamReader(System.in));

int ul;

System.out.print("Enter the upper limit: ");
ul = Integer.parseInt(keybd.readLine());

}

}

I don't understand how to use a for loop to calculate the sum.

After that I got stuck. I appreciate any help i can get thanks! :)

[JosAH]

I am trying to make a summation calculator for the following equation:

Are you sure that summation is correct? There is no dependency on i in the term to be summed so the entire thing can be reduced to (n+1)*T where T is that term.

kind regards,

Jos

[ozzyman]

You will need some math functions.

Math.pow returns the value of the first argument raised to the power of the second argument.

double Math.pow(double a, double b)

To calculate the factorial make your own loop e.g.

private int factorial(int number) {
    int counter = number;
    int answer = counter;
    while (counter > 1) {
      answer *= --counter;
    }
    return answer;
}

And then make a for-loop over your entire equation with your limits put in e.g.

double totalSum = 0;
double sum = 0;
for (i=0; i<=n; i++) {
  ...
  totalSum += sum;
}
return totalSum;

But beware whereever you add an integer to the sum, convert it to a double first, or cast it to a double.

[DavidG24]

just let n--> inf and your answer becomes

double sum = Math.sin(x); // :-)

that or modify the answer I gave for your other question regarding sums of odd factorials

David