Trigonometry & Inverse Trigonometry
Inverse Cosine
Grade 12
Question:
<p>If \(\cos^{-1}x - \cos^{-1}\left(\frac{y}{2}\right) = a\), then \(4x^2 - 4xy\cos a + y^2\) equals</p>
<p>(a) 4</p>
<p>(b) \(2\sin a\)</p>
<p>(c) \(-4\sin^2 a\)</p>
<p>(d) \(4\sin^2 a\)</p>
Step-by-Step Solution
Key Concept: Use the relationship between inverse cosines and apply algebraic manipulation.
<p>No solution provided in source text.</p>
Correct Answer: D