Sample Problems

Question 1: Find out the following limit. 

Solution: 

This limit is of the 0/0 form. Factorization can be used here.

Question 2: Find out the following limit. 

Solution: 

This limit is of the 0/0 form. Factorization can be used here.

⇒ -1

Question 3: Find out the following limit. 

Solution: 

This limit is of the indeterminate form. Rationalization can be used here.

Question 4: Find out the limit of,

Solution:

Putting the limit x tends to 2 to see the value obtained,

= Undefined.

As, it is clear that the answer is undefined, rationalize the denominator,

Determining Limits using Algebraic Manipulation

Limits give us the power to approximate functions and see the values they are approaching. Limit is not the value of the function at a particular point. It is the value which the function is approaching as one moves towards the given point. There are many ways to solve the limits, often limits are easy to solve, but sometimes they evaluate into indeterminate forms which are not defined and are difficult to estimate. The goal is to avoid these forms and solve the limits of the function. Let’s look at some algebraic ways to solve such limits.

Table of Content

  • Limits 
  • Indeterminate Forms
  • Limits using Algebraic Manipulation
  • Limits by Factoring
  • Limits by Rationalization
  • Trigonometric limits using Pythagorean Identities
  • Double angle Identities
  • Sample Problems

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Limits

A limit is a value the function or a sequence approach as the input or the index approaches some value. These concepts are essential in calculus and real analysis as they help us define continuity, differentiability, and integrals. In the formula, the limit for a function f(x) at a point x = c is usually denoted as,...

Indeterminate Forms

An indeterminate form is usually encountered where the limit involves more than one function. It is defined as an expression involving two or more whose limit cannot be determined solely from the individual functions....

Limits using Algebraic Manipulation

These techniques from algebra can help in avoiding the indeterminate forms in the limits. Some of these forms include evaluating limits by factoring and sometimes rationalizing. In the case of trigonometric functions, some other tricks such as using the Pythagorean identity or trigonometric limit using double angle identity can help us solve these limits....

Limits by Factoring

Usually, in the ratio functions consisting of polynomials, the indeterminate form stems from one of the factors occurring in the expression. For example, in the function f(x) given below, the indeterminate form is due to the factor (x – 1)....

Limits by Rationalization

In this method, indeterminate form is dealt with by rationalizing the function....

Trigonometric limits using Pythagorean Identities

Pythagorean Identities consists of following three identities:...

Double angle Identities

Following double angle identities can also be used for substitution in trigonometric functions:...

Sample Problems

Question 1: Find out the following limit....

Determining Limits using Algebraic Manipulation – FAQs

How to solve limits using algebraic manipulation?...

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