Question

Prove that(sin^2 3 A/sin^2 A)-(Cos^2 3 A/cos^2 A)=8 cos 2 A

Answer 1

Answer:

If sin A +sin^3 A =cos^2 A then how can we prove that cos^6 A - 4cos^4 A +8cos^2 = 4?

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sinA(1+sin^2A) = cos^2A

sinA(2 -cos^2A) = cos^2A

Squaring both sides,

sin^2A(4-4cos^2A +cos^4A) = cos^4A

(1-cos^2A)(4-4cos^2A +cos^4A) = cos^4A

4-4cos^2A +cos^4A-4cos^2A+4cos^4A-cos^6A = cos^4A

4 -cos^6A +4cos^4A -8cos^2A = 0

cos^6A - 4 cos^4A + 8cos^2A = 4

Hence Proved

Answer 2

Answer:

hope it helps you

Step-by-step explanation:

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