A) \[{{45}^{o}}\] and \[{{60}^{o}}\]
B) \[{{45}^{o}}\]and \[{{90}^{o}}\]
C) \[{{45}^{o}}\]only
D) \[{{90}^{o}}\]only
Correct Answer: B
Solution :
\[\cot \theta =\sin 2\theta ,\text{ }(\theta \ne n\pi )\Rightarrow 2{{\sin }^{2}}\theta \cos \theta =\cos \theta \] \[\Rightarrow \] \[\cos \theta =0\] or \[{{\sin }^{2}}\theta =\frac{1}{2}={{\sin }^{2}}\left( \frac{\pi }{4} \right)\] \[\Rightarrow \] \[\theta =(2n+1)\frac{\pi }{2}\] or \[\theta =n\pi \pm \frac{\pi }{4}\] \[\Rightarrow \] \[\theta ={{90}^{o}}\] and \[{{45}^{o}}\].
You need to login to perform this action.
You will be redirected in
3 sec
