If 2 cos theta = underoot 3 , prove that 3 sin theta - 4 sin^3 theta = 1.
Answers
Answered by
36
Answer:
Step-by-step explanation:
2 Cosθ = √3
=> Cosθ = √3/2
=> θ = 30°
Now 3 sinθ - 4 sin³θ
= Sin3(30°) (∵Sin3θ = 3Sinθ - 4Sin³θ)
= Sin90°
= 1
= R.H.S
Hence proved
Answered by
9
Answer:
Step-by-step explanation:
We have,
- 2 cos Ф = √3
So,
- cos Ф = √3/2
We know,
⇒ cos 30° = √3/2
∴ Ф = 30°
So,
- 3 sin Ф - 4 sin³ Ф = 1
We know,
- sin 3 Ф = 3 Sin Ф - 4 Sin³ Ф
Hence,
⇒ sin (3 × 30)°
⇒ sin 90°
- 1
∴ L.H.S = R.H.S
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