Functions Question 298

Question: If $ \underset{n\to \infty }{\mathop{\lim }},\frac{1-{{(10)}^{n}}}{1+{{(10)}^{n+1}}}=\frac{-\alpha }{10} $ , then give the value of $ \alpha $ is

[Orissa JEE 2005]

Options:

A) 0

B) ?1

C) 1

D) 2

Show Answer

Answer:

Correct Answer: C

Solution:

$ \underset{n\to \infty }{\mathop{\lim }},\frac{1-{{(10)}^{n}}}{1+{{(10)}^{n+1}}} $ $ =\underset{n\to \infty }{\mathop{\lim }},\frac{{{(10)}^{n}}[ {{( \frac{1}{10} )}^{n}}-1 ]}{{{(10)}^{n+1}}( 1+\frac{1}{{10^{n+1}}} )}=-\frac{1}{10} $
$ \therefore \alpha =1 $ .