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2 sin 75° sin15° =_____________________________(a) \(\frac{\sqrt{3}}{2}\)(b) \(\frac{\sqrt{2}}{\sqrt{3}}\)(c) \(\frac{1}{2}\)(d) \(\frac{1}{\sqrt{2}}\)This question was addressed to me in my homework.I need to ask this question from Trigonometric Functions of Sum and Difference of Two Angles-2 topic in section Trigonometric Functions of Mathematics – Class 11

Answer»

The correct CHOICE is (c) \(\frac{1}{2}\)

The explanation: We KNOW, 2 sin X sin y = cos (x – y) – cos (x + y)

2 sin 75° sin15° = cos (75°-15°) – cos (75°+15°)

= cos 60° – cos 90° = 1/2 – 0 = 1/2.



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