# Math Help - Modular Proof

1. ## Modular Proof

Prove
$2^b mod (2^a)-1 = 2^(bmoda)$

Very confused...

2. Consider the cases where b = a. and the case where b != a ( "b = a + k" & "2^b = 2^k * 2^a" (for some real number k))

EDIT// for glaring mistake of using the least positive number class for modulo as a real number in the proof. horrible, horrible, mistake.