Prove the truth of the following: 1 2 4 ?2^n=2^(n 1)-1
Please I do not know what to do here?

Um... not all the symbols are appearing... could you type them manually instead of copy/pasting?

I think the OP means this:


1 + 2+ 4 + ... + 2^n = 2^{(n+1)} - 1


You can demonstrate this using an inductive proof. First show that it works for the case of n = 1, then show that if it's valid for any integer n = k then it must also be valid for n = k+1. If you get stuck post back and show us what you've tried, and we'll help you through it.