Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • School
  • Explain solution RD Sharma class 12 chapter 8 Continuity exercise multiple choice question 16 maths

Explain solution RD Sharma class 12 chapter 8 Continuity exercise multiple choice question 16 maths

Answers (1)

Answer:

 The correct option is (c)

Hint:

 Use the given formula:

(i)  A function f(x) is said to be continuous at a point x = a of its domain, if

\lim _{x \rightarrow a^{+}} f(a+h)=\lim _{x \rightarrow a^{-}} f(a-h)=f(a)

Given:

 f(x)=\frac{\sqrt{a^{2}-a x+x^{2}}-\sqrt{a^{2}+a x+x^{2}}}{\sqrt{a+x}-\sqrt{a-x}}

Solution:

Using rationalization method,

\lim _{x \rightarrow 0} f(x)=\lim _{x \rightarrow 0} \frac{\left(a^{2}-a x+x^{2}\right)-\left(a^{2}+a x+x^{2}\right)}{(\sqrt{a+x}-\sqrt{a-x})\left(\sqrt{a^{2}-a x+x^{2}}+\sqrt{a^{2}+a x+x^{2}}\right)}

\lim _{x \rightarrow 0} \frac{-2 a x(\sqrt{a+x}+\sqrt{a-x})}{2 x\left(\sqrt{a^{2}-a x+x^{2}}+\sqrt{a^{2}+a x+x^{2}}\right)}

\left.\lim _{x \rightarrow 0} \frac{-a(\sqrt{a+x}+\sqrt{a-x})}{\left(\sqrt{a^{2}-a x+x^{2}}+\sqrt{a^{2}+a x+x^{2}}\right.}\right)

=\lim _{x \rightarrow 0} \frac{-2 a(\sqrt{a})}{2 a}=-\sqrt{a}

Understand that, f(x) is continuous for all x, then it is continuous at x = 0

\begin{aligned} &\lim _{x \rightarrow 0} f(x)=0 \\ &\lim _{x \rightarrow 0}-\sqrt{a}=f(0) \end{aligned}

So, the correct option is (c)

Posted by

Gurleen Kaur

View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads

Similar Questions

Trending Articles/News

anam-khan

CBSE Class 10, 12 compartment 2024 exams today for 2.5 lakh students; exam timings, guidelines
anam-khan

CBSE compartment admit card 2024 out at cbse.gov.in; exams from July 15
anam-khan

Reports saying CBSE cannot conduct board exams twice a year currently ‘totally incorrect’; board denies claims

Latest Question