If $2 \sin \left(\theta+\frac{\pi}{3}\right)=\cos \left(\theta-\frac{\pi}{6}\right)$, then $\tan \theta$
If $2 \sin \left(\theta+\frac{\pi}{3}\right)=\cos \left(\theta-\frac{\pi}{6}\right)$, then $\tan \theta$
- $\frac{-1}{\sqrt{3}}$
- $-\sqrt{3}$
- $\sqrt{3}$
- $\frac{1}{\sqrt{3}}$
Solution
$\begin{aligned}
& 2 \sin \left(\theta+\frac{\pi}{3}\right)=\cos \left(\theta-\frac{\pi}{6}\right) \\
& 2\left[\sin \theta \cos \frac{\pi}{3}+\cos \theta \sin \frac{\pi}{3}\right]=\left(\cos \theta \cos \frac{\pi}{6}+\sin \theta \sin \frac{\pi}{6}\right) \\
& \therefore 2\left(\frac{\sin \theta}{2}+\frac{\sqrt{3} \cos \theta}{2}\right)=\left(\frac{\sqrt{3} \cos \theta}{2}+\frac{\sin \theta}{2}\right) \\
& \therefore\left(\frac{\sin \theta}{2}+\frac{\sqrt{3} \cos \theta}{2}\right)=0 \Rightarrow \sin \theta+\sqrt{3} \cos \theta=0 \Rightarrow \tan \theta=-\sqrt{3}
\end{aligned}$
Asked in: MHT CET 2021 (21 Sep Shift 1)
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