Answer: A
\(\tan \theta \cos 60° = \cfrac{√3}{2}\)
or, \(\tan \theta \times \cfrac{1}{2} = \cfrac{√3}{2}\)
or, \(\tan \theta = √3 = \tan 60°\)
or, \(\theta = 60°\)
\(\therefore\) \(\sin(\theta - 15°) = \sin(60° - 15°)\)
\( = \sin 45° = \cfrac{1}{√2}\).
\(\tan \theta \cos 60° = \cfrac{√3}{2}\)
or, \(\tan \theta \times \cfrac{1}{2} = \cfrac{√3}{2}\)
or, \(\tan \theta = √3 = \tan 60°\)
or, \(\theta = 60°\)
\(\therefore\) \(\sin(\theta - 15°) = \sin(60° - 15°)\)
\( = \sin 45° = \cfrac{1}{√2}\).