Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Indefinite Integration

Question:

Find: $\int \cos^3 x e^{\ln \sin x} dx$

Options:

$\frac{\cos^4 x}{4} + C$

$-\frac{\sin^4 x}{4} + C$

$-\frac{\cos^4 x}{4} + C$

$\frac{\sin^4 x}{4} + C$

Correct Answer:

$-\frac{\cos^4 x}{4} + C$

Explanation:

The correct answer is Option (3) → $-\frac{\cos^4 x}{4} + C$

Let, $I = \int \cos^3 x e^{\ln \sin x} dx$

Or, $I = \int \cos^3 x \sin x dx$

Put, $\cos x = t ⇒-\sin x dx = dt$

$∴I = -\int t^3 dt$

Or, $I = -\frac{t^4}{4} + C$

Or, $I = -\frac{\cos^4 x}{4} + C$