Assume that $n$ is a positive integer. Use mathematical induction to prove each statement
S by following these steps. See Example $I$.
(a) Verify the statement for $n=1$
(b) Write the statement for $n=k$
(c) Write the statement for $n=k+1$
(d) Assume the statement is true for $n=k$. Use algebra to change the statement in part
(b) to the statement in part (c).
(e) Write a conclusion based on Steps (a)-(d).
$$2+4+8+\dots+2^{n}=2^{n+1}-2$$