∫ dx/(x²-a²)

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  1. 2a log (x-a)
  2. 2a-sec(x-a)+ C
  3. 1/2a log|(x-a)/(x+a)| 
  4. a- Sin(x-a)+ cosec(x-a) +C

Answer (Detailed Solution Below)

Option 3 : 1/2a log|(x-a)/(x+a)| 
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Detailed Solution

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Given:

The integral to solve is: ∫ dx / (x2 - a2)

Concept Used:

The integral of the given type can be solved using partial fraction decomposition and standard integral formulas. The standard integral is:

∫ dx / (x2 - a2) = (1 / 2a) log|(x - a) / (x + a)| + C

Here:

  • x: Variable of integration

  • a: A constant

  • log: Refers to the natural logarithm (ln)

Calculation:

We rewrite the given integral using partial fraction decomposition:

1 / (x2 - a2) = 1 / [(x - a)(x + a)]

Using partial fractions:

1 / [(x - a)(x + a)] = A / (x - a) + B / (x + a)

Solving for A and B, we find:

A = 1 / 2a, B = -1 / 2a

Substituting back:

1 / [(x - a)(x + a)] = (1 / 2a) / (x - a) - (1 / 2a) / (x + a)

Integrating term by term:

∫ dx / (x2 - a2) = (1 / 2a) ∫ dx / (x - a) - (1 / 2a) ∫ dx / (x + a)

⇒ (1 / 2a) log|x - a| - (1 / 2a) log|x + a| + C

⇒ (1 / 2a) log|(x - a) / (x + a)| + C

Latest Army Havildar SAC Updates

Last updated on Jul 1, 2025

-> The Indian Army has released the Exam Date for Indian Army Havildar SAC (Surveyor Automated Cartographer).

->The Exam will be held on 9th July 2025.

-> Interested candidates had applied online from 13th March to 25th April 2025.

-> Candidates within the age of 25 years having specific education qualifications are eligible to apply for the exam.

-> The candidates must go through the Indian Army Havildar SAC Eligibility Criteria to know about the required qualification in detail. 

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