This is a Test of Mathematics Solution Subjective 155 (from ISI Entrance). The book, Test of Mathematics at 10+2 Level is Published by East West Press. This problem book is indispensable for the preparation of I.S.I. B.Stat and B.Math Entrance.

Also visit: I.S.I. & C.M.I. Entrance Course of Cheenta

## Problem

** Evaluate: **

## Solution

**As the title suggests the modification of this problem will be, that we will solve a more general series and then use a specific value to arrive at the solution of this problem.**

**First let us consider the following limit:**

**Observe carefully that using k=1 in this limit, we get the limit that has been asked to evaluate.**

**Now**

**Let’s substitute **

**Now we can change the summand to an integral**

** (As the term is an ‘n’ free term)**

**So we see the solution is** ** **

**Substituting k=1, we get **

** **