Q.If \( \cos^2\theta – \sin^2\theta = \frac{1}{2} \), then what is the value of \( \tan\theta \)? (a) \(\frac{1}{\sqrt3}\) (b) \(\sqrt3\) (c) 1 (d) None of the above
Answer: A
Given: \(\cos^2\theta – \sin^2\theta = \frac{1}{2}\) Or, \(2\cos^2\theta – 2\sin^2\theta = 1\) Or, \(2\cos^2\theta – 2\sin^2\theta = \sin^2\theta + \cos^2\theta\) Or, \(–2\sin^2\theta – \sin^2\theta = \cos^2\theta – 2\cos^2\theta\) Or, \(–3\sin^2\theta = –\cos^2\theta\) Or, \(3\sin^2\theta = \cos^2\theta\) Or, \(\frac{\sin^2\theta}{\cos^2\theta} = \frac{1}{3}\) Or, \(\tan^2\theta = \frac{1}{3}\) Therefore, \(\tan\theta = \frac{1}{\sqrt{3}}\)
Similar Questions