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Asked by Aaron Moris on 11 Apr 2011

What is the product if the question is write a program that calculates and prints the sum of the even integers from 2 to 30?

Answer by Florin Neacsu on 11 Apr 2011

2+4+6+...+30=2(1+2+3+...+15)=2*(15*16)/2=15*16

So 2+4+...+n = floor(n/2)*(floor(n/2)+1).

Regards, Florin

Answer by Matt Fig on 11 Apr 2011

The product would be the sum of the even integers from 2 to 30 ;-).

Seriously, what have you tried so far on this homework problem?

Paulo Silva on 11 Apr 2011

I hate when it takes more time to understand what people want than to make their answer!

Answer by Doug Eastman on 11 Apr 2011

or

sum(2:2:30)

Paulo Silva on 11 Apr 2011

that's simple but if you change the start value from 2 to 1 you do the sum of odd numbers instead, also if the last value is 31 or some odd number the result won't be correct, unfortunately that's not very flexible code.

Paulo Silva on 11 Apr 2011

btw that does work and is a good answer for the question (only if the values don't change), +1 vote

Answer by Matt Tearle on 11 Apr 2011

disp(240)

Or, for pedants who claim that evaluation is not the same as calculation,

disp(239+1)

Sean de Wolski on 11 Apr 2011

This is definitely the most compact and efficient way to do this. +1.

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