Let n be an integer. Prove that if n^3 is even, then n is even.
The Attempt at a Solution
Suppose n is even. That is n=2m, for some mεZ.
Since 4m^3 is an integer, n^3 will be even.
Now, i proved that if n is even, then n^3 is even. So would this be a valid proof in this context?