Q. If the sum of $n$ terms of the series $2^{3} + 4^{3} + 6^{3} + ...$ is 3528, then $n$ equals to

A) 10
B) 7
C) 8
D) 6
Explanation

(d)
Given series is $2^{3} + 4^{3} + 6^{3} + ...$
$\therefore T_{n} = (2n)^{3} = 8n^{3}$
$\therefore\Sigma T_{n} = 8\Sigma n^{3} = \frac{8n^{2}(n + 1)^{2}}{4}$
$\Rightarrow 3528 = 2n^{2}(n + 1)^{2} \Rightarrow n = 6$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

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