If sin B=1/4, pi/2 < B < pi, find the exact value of sin 3B

Expert Answers

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We know that sin 3x = 3 sin x - 4 (sin x)^3

Now sin B is given as 1/4.

sin 3B = 3 sin B - 4(sin B)^3

=> 3* (1/4) - 4(1/4)^3

=> 3/4 - 1/16

=> (12 - 1)/16

=> 11/16

Therefore sin 3B = 11/16

Approved by eNotes Editorial Team
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