Question

2 sin A =1 show that 3 cosA - 4cos^3 A

Answer 1

sinA=1/2

cosA=√3/2 [ using rt angle property]

cos^3(A) = 3√3/8

substituting

3cosA-4cos^3(A)

= 3*√3/2–4*3√3/8

=(3√3/2) – (3√3/2)

= 0

@skb