Maths > Limits > 6.0 Some Standard Methods of Evaluation of Limits:

  Limits
    1.0 Introduction
    2.0 Definition of Limit - In a different form:
    3.0 Conditions for existence of Limit
    4.0 Some Standard Limits
    5.0 Algebra of limits
    6.0 Some Standard Methods of Evaluation of Limits:
    7.0 Indeterminate Forms:
    8.0 Sandwich Theorem / Squeeze Play Theorem:
    9.0 L'Hospital's Rule for evaluation of limits:

6.1 Factorization
Question 13.

Evaluate $\mathop {\lim }\limits_{x \to 2} \frac{{{x^6} - 24x - 16}}{{{x^3} + 2x - 12}}$.

Solution:

$\mathop {\lim }\limits_{x \to 2} \frac{{{x^6} - 24x - 16}}{{{x^3} + 2x - 12}} = \mathop {\lim }\limits_{x \to 2} \frac{{(x - 2)({x^5} + 2{x^4} + 4{x^3} + 8{x^2} + 16x + 8)}}{{(x - 2)({x^2} + 2x + 6)}}$


$ = \mathop {\lim }\limits_{x \to 2} \frac{{({x^5} + 2{x^4} + 4{x^3} + 8{x^2} + 16x + 8)}}{{({x^2} + 2x + 6)}}$


$ = \mathop {\lim }\limits_{x \to 2} \frac{{{{(2)}^5} + 2{{(2)}^4} + 4{{(2)}^3} + 8{{(2)}^2} + 16(2) + 8}}{{{{(2)}^2} + 2(2) + 6}}$


$ = \frac{{168}}{{14}}$


$ = 12$

Question 14.

Evaluate $\mathop {\lim }\limits_{x \to 9} \frac{{\sqrt x - 3}}{{x - 9}}$.

Solution:

$\mathop {\lim }\limits_{x \to 9} \frac{{\sqrt x - 3}}{{x - 9}} = \mathop {\lim }\limits_{x \to 9} \frac{{\sqrt x - 3}}{{\left( {\sqrt x - 3} \right)\left( {\sqrt x + 3} \right)}}$

$ = \mathop {\lim }\limits_{x \to 9} \frac{1}{{\left( {\sqrt x + 3} \right)}}$

$ = \frac{1}{{\sqrt 9 + 3}}$

$ = \frac{1}{6}$

Improve your JEE MAINS score
10 Mock Test
Increase JEE score
by 20 marks
Detailed Explanation results in better understanding
Exclusively for
JEE MAINS and ADVANCED
9 out of 10 got
selected in JEE MAINS
Lets start preparing
DIFFICULTY IN UNDERSTANDING CONCEPTS?
TAKE HELP FROM THINKMERIT DETAILED EXPLANATION..!!!
9 OUT OF 10 STUDENTS UNDERSTOOD