ExamBro
ExamBro
KCET · Maths · Indefinite Integration

If '\(n\)' is a natural number, then \(\int \dfrac{\sin^n x}{\cos^{n+2} x}\,dx = \)

  1. A \(\dfrac{\tan^{n-1} x}{n - 1} + C\)
  2. B \(\dfrac{\tan^n x}{n} + C\)
  3. C \(\dfrac{\tan^{n+2} x}{n + 2} + C\)
  4. D \(\dfrac{\tan^{n+1} x}{n + 1} + C\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(\dfrac{\tan^{n+1} x}{n + 1} + C\)

Step-by-step Solution

Detailed explanation

The given integral is \(I = \int \dfrac{\sin^n x}{\cos^{n+2} x} \,dx\)

This can be rewritten as:

\(I = \int \left(\dfrac{\sin x}{\cos x}\right)^n \cdot \dfrac{1}{\cos^2 x} \,dx\)

\(I = \int \tan^n x \sec^2 x \,dx\)

Let \(\tan x = t\), then \(\sec^2 x \,dx = dt\)

Substituting these into the integral, we get:

\(I = \int t^n \,dt\)

\(I = \dfrac{t^{n+1}}{n+1} + C\)

\(I = \dfrac{\tan^{n+1} x}{n+1} + C\)

Answer: \(\dfrac{\tan^{n+1} x}{n + 1} + C\)