Q.If \(x^2 = \sin^2 30^\circ + 4\cot^2 45^\circ - \sec^2 60^\circ\), then the value of \(x\) is — (a) \(\pm 1\) (b) \(\pm \cfrac{1}{2}\) (c) \(\pm \cfrac{1}{\sqrt2}\) (d) \(\pm \cfrac{1}{\sqrt3}\)
Answer: B
Given: \(x^2 = \sin^2 30^\circ + 4\cot^2 45^\circ - \sec^2 60^\circ\) ⇒ \(x^2 = \left(\cfrac{1}{2}\right)^2 + 4(1)^2 - 2^2\) ⇒ \(x^2 = \cfrac{1}{4} + 4 - 4\) ⇒ \(x^2 = \cfrac{1}{4}\) ⇒ \(x = \sqrt{\cfrac{1}{4}} = \pm \cfrac{1}{2}\)
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