Summing a Series: Is this correct??

• 10-02-2011, 05:38 AM
son012189
Summing a Series: Is this correct??
Write a program to sum the following series:
(1/3) + (3/5) + (5/7) + (7/9) + (9/11) + (11/13) + ... + (95/97) + (97/99)

This is my attempt.
Code:

```public class SummingSeries {         public static void main(String[] args) {                 double sum = 0.0;                 for(double i = 1; i <= 99; i++) {                         sum += ((i+2)/(i+4));                 }                 System.out.println("The sum is " + sum);         } }```
This is the output I get.
Quote:

The sum is 92.73308433232398
Is my output correct? I have no idea what the desired output is supposed to be so I need to know if 92.73308433232398 is actually the sum of the series mentioned above. Is there anything wrong with my code? I think my code is correct but I'm not sure.
• 10-02-2011, 06:48 AM
JosAH
Re: Summing a Series: Is this correct??
Quote:

Originally Posted by son012189
Write a program to sum the following series:
(1/3) + (3/5) + (5/7) + (7/9) + (9/11) + (11/13) + ... + (95/97) + (97/99)

This is my attempt.
Code:

```public class SummingSeries {         public static void main(String[] args) {                 double sum = 0.0;                 for(double i = 1; i <= 99; i++) {                         sum += ((i+2)/(i+4));                 }                 System.out.println("The sum is " + sum);         } }```
This is the output I get.

Is my output correct? I have no idea what the desired output is supposed to be so I need to know if 92.73308433232398 is actually the sum of the series mentioned above. Is there anything wrong with my code? I think my code is correct but I'm not sure.

Take a few examples for 'i', say 1, 2 and 3 and see if you get the correct terms: 3/5, 4/6, 5/7; what is that 4/6 doing there?

kind regards,

Jos
• 10-02-2011, 08:09 PM
son012189
Re: Summing a Series: Is this correct??
I see my mistake now thanks. I fixed my code.

Code:

```public class SummingSeries {         public static void main(String[] args) {                 double sum = 0.0;                 for(double i = 1; i <= 49; i++) {                         sum += ((2*i-1)/(2*i+1));                 }                 System.out.println("The sum is " + sum);         } }```
Is my code correct now? or is there something else I need to fix?
• 10-02-2011, 08:36 PM
JosAH
Re: Summing a Series: Is this correct??
Quote:

Originally Posted by son012189
I see my mistake now thanks. I fixed my code.

Code:

```public class SummingSeries {         public static void main(String[] args) {                 double sum = 0.0;                 for(double i = 1; i <= 49; i++) {                         sum += ((2*i-1)/(2*i+1));                 }                 System.out.println("The sum is " + sum);         } }```
Is my code correct now? or is there something else I need to fix?

It's fine now; you also could've done this:

Code:

```for (double i= 1; i <= 97; i+= 2)   sum+= i/(i+2);```
kind regards,

Jos
• 10-05-2011, 05:36 PM
son012189
Re: Summing a Series: Is this correct??
I see. Thanks.