Recent content by vyro

is that valid as a proof though, starting from the conclusion and then reaffirming it?

yeah, i redid the first one using a proof by induction. thanks for the response though.

Also, another proof: Homework Statement Prove that for each a that exists in real numbers and n that exists in natural numbers there exists a rational r such that abs(a-r) < 1/n Homework Equations The Attempt at a Solution I believe it has something to do with the theorem on density of...

Homework Statement Prove that 2^n + 3^n is a multiple of 5 for all odd n that exist in the set of natural numbers. Homework Equations The Attempt at a Solution Suppose the contrary perhaps and do a proof by contradiction? Perhaps induction? edit: done, thank you. please look at second proof :)