n (n-1)
if n is even, then the product is even times odd = 2 times something
if n is odd, then (n-1) is even and the product is odd time even = something*2
For every integer n, prove n^2-n is even. Can someone help me?
2 answers
n(n-1)
If n is even then n-1 is odd even times odd = even (3)(4) = 12
if n is odd then n-1 is even.. odd times even = even (5)(4) = 20
This shows it is even, but a proof might want more...
You want to prove that n(n-1) is divisible by 2
If n is even then n-1 is odd even times odd = even (3)(4) = 12
if n is odd then n-1 is even.. odd times even = even (5)(4) = 20
This shows it is even, but a proof might want more...
You want to prove that n(n-1) is divisible by 2