Assume
Then
The last step was true since
Prove by induction that 3^n >= 1 + 2^n
I am trying to prove this by showing 3^(k+1) = 3*3^k >= 1 + 2^(k+1), so I was using an inductive substitution of putting 3(1+2^k) on the left side of the inequality, but it doesn't seem to get me anywhere. I can't think of how else to do this.