Examveda

If $$\theta + \phi = \frac{\pi }{2}$$   and $$\sin \theta = \frac{1}{2},$$   then the value of $${\text{sin}}\phi $$  is?

A. 1

B. $$\frac{1}{{\sqrt 2 }}$$

C. $$\frac{1}{2}$$

D. $$\frac{{\sqrt 3 }}{2}$$

Answer: Option D

Solution (By Examveda Team)

$$\eqalign{ & \theta + \phi = \frac{\pi }{2} \cr & \theta + \phi = {90^ \circ }\,......(i) \cr & \sin \theta = \frac{1}{2} \cr & \sin \theta = {\text{sin 3}}{0^ \circ } = \frac{1}{2}\,......(ii) \cr & {\text{Put }}\theta = {30^ \circ }{\text{ in equation (i)}} \cr & {30^ \circ } + \phi = {90^ \circ } \cr & \phi = {60^ \circ } \cr & \sin \phi = \sin {60^ \circ } = \frac{{\sqrt 3 }}{2} \cr} $$

This Question Belongs to Arithmetic Ability >> Trigonometry

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