Question Detail

MTH 101 Mathematical Induction Objective Question

Question

Prove by induction that log(a) + log(a²) + log(a³) + ... + log(a^n) = n(n+1)/2 × log(a) for n ≥ 1.
Options
A True
Correct Answer
B False
C Only for a>1
D Only for n even
Correct Answer

Option A is the correct answer.

Detailed Explanation

log(a) + log(a²) + ... + log(a^n) = log(a×a²×...×a^n)=log(a^{1+2+...+n})=log(a^{n(n+1)/2})=n(n+1)/2 × log(a). Base case n=1 ✔. Inductive step follows similarly.

Hint

Use log properties and sum of first n integers.

Question Info