$\frac{\cos 12^{\circ}-\sin 12^{\circ}}{\cos 12^{\circ}+\sin 12^{\circ}}+\frac{\sin 147^{\circ}}{\cos…

$\frac{\cos 12^{\circ}-\sin 12^{\circ}}{\cos 12^{\circ}+\sin 12^{\circ}}+\frac{\sin 147^{\circ}}{\cos 147^{\circ}}=$
  1. -2
  2. 0
  3. -1
  4. 1

Solution

$\frac{\cos 12^{\circ}-\sin 12^{\circ}}{\cos 12^{\circ}+\sin 12^{\circ}}+\frac{\sin 147^{\circ}}{\cos 147^{\circ}}$ $=\frac{\cos 12^{\circ}-\cos 78^{\circ}}{\cos 12^{\circ}+\cos 78^{\circ}}+\tan 147^{\circ}$ $=\frac{-2 \sin 45^{\circ} \sin \left(-33^{\circ}\right)}{2 \cos 45^{\circ} \cos 33^{\circ}}+\tan \left(180^{\circ}-33^{\circ}\right)=\tan 45^{\circ} \tan 33^{\circ}-\tan 33^{\circ}$ $=\tan 33^{\circ}-\tan 33^{\circ}=0$

Asked in: MHT CET 2020 (14 Oct Shift 2)

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