Use the method of mathematical induction to prove that, for

I've done the first stage, which is to show that it's true for n=1 (both sides are equal to 2 in said situation). I can easily do the assumption stage, which is simply to substitute in n=k. I know that the next stage involves showing it's true for n=k+1 but I can't seem to do this correctly. I think my memory is slightly fuzzy and my notes are just confusing me. Any help would be appreciated.

Edit: woops, posted this in pre-calc. >.< move this to pre-algebra and algebra if necessary, but please don't delete the thread - figuring out that latex took me hours.