Question

1 5 If sin B = then 3 cos B - 4 cos B is equal to?​

Answer 1

Answer:

Step-by-step explanations: sinB = 1/2 cosB = cosB= √1–sin²B = √1–¼ = √¾

∴ B = cos-1 (√3/2) = 30°

∴ 3cosB – 4cos³B = cos3B = cos(3×30°)

= cos = 90° = 0

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