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Question: Using half-angle formula, find the value of tan 15°.


A ) 36
B ) 2 - 3
C ) 2 +3
D ) 233

Steps to derive

1 tan 15° = 1-cos 30°sin 30°
 [Use: tan (x2) = 1 - cos xsinx; 15° = 12 · 30°.]

2 = 1-3212
 [cos 30° = 32; sin 30° = 12.]

3 = 2 - 3



Hence the right answer is Option B

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