ExamBro
ExamBro
AP EAMCET · Maths · Trigonometric Ratios & Identities

If \(\alpha\) is the maximum value and \(\beta\) is the minimum value of \(\cos ^2 \frac{x}{4}+\sin \frac{x}{4}\), \(x \in R\), then \(\alpha-\beta=\)

  1. A \(\frac{1}{4}\)
  2. B \(\frac{9}{4}\)
  3. C \(2\)
  4. D 3
Verified Solution

Answer & Solution

Correct Answer

(B) \(\frac{9}{4}\)

Step-by-step Solution

Detailed explanation

Let \(y = \sin \frac{x}{4}\). Since \(x \in R\), \(y \in [-1, 1]\). The expression becomes \(f(y) = (1 - \sin^2 \frac{x}{4}) + \sin \frac{x}{4} = 1 - y^2 + y\). Consider \(g(y) = -y^2 + y + 1\) for \(y \in [-1, 1]\). The vertex of the parabola is at…