Functions Question 167

Question: The value of $ \underset{x\to \infty }{\mathop{\lim }},\sqrt{a^{2}x^{2}+ax+1}-\sqrt{a^{2}x^{2}+1} $ is

Options:

A) $ \frac{1}{2} $

B) 1

C) $ 2 $

D) None of these

Show Answer

Answer:

Correct Answer: A

Solution:

$ \underset{x\to \infty }{\mathop{\lim }}\sqrt{a^{2}x^{2}+ax+1}-\sqrt{a^{2}x^{2}+1} $ $ =\underset{x\to \infty }{\mathop{\lim }}\frac{ax}{,\sqrt{a^{2}x^{2}+ax+1}+\sqrt{a^{2}x^{2}+1}} $ $ =\underset{x\to \infty }{\mathop{\lim }}\frac{a}{,\sqrt{a^{2}+\frac{a}{x}+\frac{1}{x^{2}}}+\sqrt{a^{2}+\frac{1}{x^{2}}}}=\frac{a}{2a}=\frac{1}{2} $ .