Class 9-10 Math Solution Exercise 9.2
Exercise 9.2: Trigonometric Ratios of Specific Angles Solution: Given, $\cos\theta = \frac{1}{2}$ or, $\cos\theta = \cos 60^\circ$ or, $\theta = 60^\circ$ Now, $\cot\theta = \cot 60^\circ = \frac{1}{\sqrt{3}}$ Answer: a) $\frac{1}{\sqrt{3}}$ Solution: Given Expression $= \cos^4\theta – \sin^4\theta$ $= (\cos^2\theta)^2 – (\sin^2\theta)^2$ $= (\cos^2\theta + \sin^2\theta)(\cos^2\theta – \sin^2\theta)$ $= 1 \times \frac{1}{3} \quad \left[\because \cos^2\theta…