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SSC CGL 2018 PYQ — Question 39

SSC CGL Tier II Quant - 09/03/2018 • Quantitative Aptitude • Q39

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What is the value of 2 sin 15º cos 15º – 4 sin3 15º cos 15º ?

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Correct answer: C

Explanation

The correct answer is Option 3 i.e. √3/4

Application

2 sin 15° cos 15° – 4 sin3 15° cos 15°

= sin 30° – 2sin 30° sin2 15°

= sin 30° (1 – 2sin2 15°)

= sin 30° cos 30°

= 1/2 × √3/2

= √3/4