Q. Let $n = 2006!$. Then $\frac{1}{\log_{2}n} + \frac{1}{\log_{3}n} + ... + \frac{1}{\log_{2006}n}$ is equal to

A) 2006
B) 2005
C) $2005!$
D) 1
Explanation

(d)
Given, $n = 2006!$
$\therefore\ \frac{1}{\log_{2}n} + \frac{1}{\log_{3}n} + ... + \frac{1}{\log_{2006}n}$
$= \log_{n}{2 + \log_{n}{3 + ... + \log_{n}2006}}$
$= \log_{n}{(2.3.4.\ \ldots.2006)}$
$= \log_{n}{(2006!) = \log_{n}{n = 1}}$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.