# [racket] Sum of Even

 From: Gregory Woodhouse (gregwoodhouse at me.com) Date: Tue Sep 25 11:45:32 EDT 2012 Previous message: [racket] Sum of Even Next message: [racket] Sum of Even Messages sorted by: [date] [thread] [subject] [author]

```You may have shown in a mathematics class that

1 + 2 + ... +  n = n(n + 1)/2

Do you recall how you did it? What was the induction step?

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On Sep 25, 2012, at 8:04 AM, Ashley Fowler <afowler2 at broncos.uncfsu.edu> wrote:

> I am trying to do a recursive analysis on the Sum of even numbers function. So far I have already defined the function. I have found the base case. The hard part is finding the non-recursive definition. I'm having trouble of what non-recursive definition even means.
>
> Step 1 - Base case: sumEven(N) = 2, if N = 1
>
> Step 2 - Non-recursive definition =
>
> (define sumEven
>     (lambda (N)
>       (cond((= N 1) 2)
>            ((> N 0) (*(+ N 1)N)))))
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