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# GCSE Maths - Proving watch

1. Please could someone help me out with this question:
'n is an integer. Prove algebraically that the sum of 1/2n(n+1) and 1/2(n+1)(n+2) is always a square number.'

I got to n^2 + 2n + 1 (which got me 1 of the 2 marks) but i don't get what you do with this equation to prove that it will always equal a square number? Help would be appreciated
2. (Original post by datters)
Please could someone help me out with this question:
'n is an integer. Prove algebraically that the sum of 1/2n(n+1) and 1/2(n+1)(n+2) is always a square number.'

I got to n^2 + 2n + 1 (which got me 1 of the 2 marks) but i don't get what you do with this equation to prove that it will always equal a square number? Help would be appreciated
n^2 + 2n + 1 = (n+1)^2

You need to use your brain a bit and notice how you can turn the polynmial (not an equation) into an integer squared.

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