Consider the numerical pyramid below, formed by simply putting down the series of odd numbers into a pyramid.

           1
         3   5
       7   9   11
    13  15  17   19
      . . .

Find a formula for the sum of the numbers in the nth row, and prove it.

(In reply to u dont need a hammer to crack a nut by anand)

Anand,

If you read my solution (and yours) you realize that you stated a formula for the last number in row n-1. Whereas I generated a formula for the first number in row n. As you pointed out, my formula is just your formula +2.

Now, you simply STATED what your formula is. So did I, at first... but then Charlie called me on it... and I generated the formula (using the calculus of differences, not the same thing as integral calculus).

If you wish to avoid using your hammer to crack this nut, then you need to show WHY your formula works. You did not do this.

--- SK

Posted by SilverKnight on 2003-10-16 17:08:32