Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Indefinite Integration

Question:

The value of $∫\frac{1}{\sqrt{x^2+8x+9}}dx=$ is (Given C constant of integration)

Options:

$log[(x+4)+\sqrt{x^2+8x+9}]+C;$

$log[(x+4)-\sqrt{x^2+8x+9}]+C;$

$log[(x-4)+\sqrt{x^2-8x+9}]+C;$

$log[(x-4)-\sqrt{x^2+8x-9}]+C;$

Correct Answer:

$log[(x+4)+\sqrt{x^2+8x+9}]+C;$

Explanation:

The correct answer is Option (1) → $\log[(x+4)+\sqrt{x^2+8x+9}]+C$

$∫\frac{1}{\sqrt{x^2+8x+9}}dx$

$=∫\frac{1}{(x+4)^2-(\sqrt{7})^2}dx$

$=\log|(x+4)+\sqrt{x^2+8x+9}|+C$