Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Indefinite Integration

Question:

The integral $∫\frac{dx}{\sqrt{\frac{1}{2}-5x-x^2}}$ is equal to :

Options:

$sin^{-1}\frac{2x+5}{3\sqrt{2}}+C$

$sin^{-1}\frac{2x+5}{3\sqrt{3}}+C$

$sin^{-1}\frac{2x-5}{3\sqrt{2}}+C$

$sin^{-1}\frac{2x-5}{3\sqrt{3}}+C$

Correct Answer:

$sin^{-1}\frac{2x+5}{3\sqrt{3}}+C$

Explanation:

The correct answer is Option (2) → $\sin^{-1}\frac{2x+5}{3\sqrt{3}}+C$

$I=∫\frac{dx}{\sqrt{\frac{1}{2}-5x-x^2}}$

$∫\frac{dx}{\sqrt{\frac{27}{4}-(x+\frac{5}{2})^2}}$

$=\sin^{-1}(\frac{x+\frac{5}{2}}{\frac{3\sqrt{3}}{2}})+C$

$=\sin^{-1}(\frac{2x+5}{3\sqrt{3}})+C$