Careers360 Logo
Rules of Changing Branch in IIIT - How to Change BTech Branch in IIITs

L’ Hospital’s Rule - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #JEE Main

Quick Facts

  • L’ Hospital’s Rule is considered one the most difficult concept.

  • 189 Questions around this concept.

Solve by difficulty

If f(1)=1,f'(1)=2\; then\;      is

If f(x) is a differentiable function in the interval (0, ∞) such that f(1) = 1 and  \lim_{t\rightarrow x} \frac{t^{2}f(x)-x^{2}f(t)}{t-x} = 1,  for each x> 0 , then f(3/2) is equal to :

Using the method of L’ Hospital, evaluate the limit \lim _{x \rightarrow \infty} \frac{x(4 x+1)^2}{(x+4)\left(x^2+6 x-1\right)}:

\mathrm{ \lim _{x \rightarrow \pi / 3}\left(\frac{\tan ^3 x-3 \tan x}{\cos \left(x+\frac{\pi}{6}\right)}\right) \text { is equal to }}

\mathrm{ If\, \, f(x)=\left(\frac{x-5+\frac{6}{x}}{x-3+\frac{2}{x}}\right), x \in \mathbb{R}-\{0,1,2\} \, \, then \lim _{x \rightarrow 2} f(x) \, \, equals}

Apply to Amity University, Noida B.Tech Admissions 2024

B.Tech/B.Arch Admissions OPEN

\mathrm{ \lim _{x \rightarrow 0}\left\{\frac{e^{x^2}-\cos x}{x^2}\right\} \text { is equal to }}

\mathrm{ \lim _{x \rightarrow 0}\left\{\frac{\cos 4 x-1}{x}\right\} \text { equals } }

Amity University, Noida B.Tech Admissions 2024

Asia's Only University with the Highest US & UK Accreditation

UPES B.Tech Admissions 2024

Ranked #52 among universities in India by NIRF | Highest CTC 50 LPA | 100% Placements

\mathrm{ \lim _{x \rightarrow a}\left\{\frac{x^a-a^x}{x^x-a^a}\right\} \text { is equal to }}

\mathrm{ \text { If } f(x)=-\sqrt{\left(25-x^2\right)} \text {, then } \lim _{x \rightarrow 1}\left\{\frac{f(x)-f(1)}{x-1}\right\} \text { equals }}

JEE Main Exam's High Scoring Chapters and Topics
This free eBook covers JEE Main important chapters & topics to study just 40% of the syllabus and score up to 100% marks in the examination.
Download EBook

\mathrm{ \lim _{x \rightarrow 1}\left(\frac{x^2-1}{x \ln x}\right) \text { equals }}

Concepts Covered - 1

L’ Hospital’s Rule

L’Hospital’s Rule

L’Hospital’s Rule states that, if \lim_{x\rightarrow a}\;\frac{f(x)}{g(x)} \ is\ of\ \frac{0}{0} or\ \frac{\infty}{\infty}\,form, then differentiate numerator and denominator till this intermediate form is removed.

i.e., \lim_{x\rightarrow a}\;\frac{f(x)}{g(x)}=\lim_{x\rightarrow a}\;\frac{f'(x)}{g'(x)},

But, if we again get the indeterminate form  \frac{0}{0} or \frac{\infty}{\infty}, then,\lim_{x\rightarrow a}\;\frac{f(x)}{g(x)}=\lim_{x\rightarrow a}\;\frac{f'(x)}{g'(x)}=\lim_{x\rightarrow a}\;\frac{f''(x)}{g''(x)} (so we differentiate numerator and denominator again)

And this process is continued till the indeterminate form  \frac{0}{0} or \frac{\infty}{\infty}  is removed.

Note:

We do not use quotient rule of differentiation here. Numerator and denominator have to be differentiated separately.

 

Some Application of L’Hospital’s Rule.

\\\text{(i)}\;\;\;\lim_{x\rightarrow 0}\;\frac{\sin x}{x}=\lim_{x\rightarrow 0}\;\frac{\cos x}{1}=1\\\\\text{(ii)}\;\;\;\lim_{x\rightarrow \infty}\;\frac{\log_e x}{x}=\lim_{x\rightarrow \infty}\;\frac{1/x}{1}=0\\\\\text{(iii)}\;\;\;\lim_{x\rightarrow 0}\;\frac{\log_e (1+x) }{x}=\lim_{x\rightarrow 0}\;\frac{\frac{1}{1+x}}{1}=1

 

Note:

In some cases, L’Hospital’s Rule fails to evaluate limit

For example,

\\\lim_{x\rightarrow \infty }\;\frac{x+\cos x}{x-\sin x}\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\left ( \frac{\infty}{\infty}\;\text{form} \right )\\\\\text{\;}\;\;\;\;=\lim_{x\rightarrow \infty }\;\frac{1-\sin x}{1-\cos x},\;\text{which\;is\;cannot be\;calculated}\\\\\text{The correct value of this limit is}\\\\\lim_{x\rightarrow \infty }\;\frac{x+\cos x}{x-\sin x}=\lim_{x\rightarrow \infty }\;\frac{1+\frac{\cos x}{x}}{1-\frac{\sin x}{x}}=\frac{1+0}{1-0}=1

Study it with Videos

L’ Hospital’s Rule

"Stay in the loop. Receive exam news, study resources, and expert advice!"

Books

Reference Books

L’ Hospital’s Rule

Mathematics for Joint Entrance Examination JEE (Advanced) : Calculus

Page No. : 2.27

Line : 26

E-books & Sample Papers

Get Answer to all your questions

Back to top