Answer to Question 1-3

Question. What is the value of sum 1 + 2/3 + 4/9 + 8/27 + ... ? (The sum is infinite, and each term is 2/3 of the previous term.)

Answer. Use the formula ∑^∞_k=1(r^k) = 1/(1−r), with r = 2/3. That gives 1/(1/3) = 3.