Trigonometric Functions
- The general solution of \(2\cos^2\theta+3\sin\theta=0\) is Answer: D. θ=nπ+(-1)ⁿ(-π/6),\ ninmathbb Z 2-2sin²θ+3sinθ=0⇒(2sinθ+1)(sinθ-2)=0⇒sinθ=-1/2 . 1
- The value of \(\tan^{-1}2+\tan^{-1}3\) is Answer: D. 3π/4 Since 2·3>1 and both are positive, the sum =π+tan⁻¹2+3/1-6=π-fracπ4=3π/4 . 1
- In \(\triangle ABC\), \(a=3,\ b=5,\ c=7\). Then angle \(C\) is Answer: A. 2π/3 cos C=9+25-49/2·3·5=-1/2⇒ C=2π/3 . 1