how would you prove by contradiction that if n is even then n^2 is even??
To prove by contradiction you assume the opposite of what is stated, ie that is odd.
As you are starting with an even number, then instead of , lets use .
, therefore if (intergers), is always even.
This is how I would do it anyway, I am sure there are different methods out there.
ps does anyone know how to do the 'member of' sign in your maths formatting thing?