Consider the following: I − sin ⁡ 6 α = cos ⁡ 2 α ( cos ⁡ 4 α − 3 cos ⁡ 2 α + 3 ) II.cos 8 α−sin 8 α=2sin 2 α(1−cos 4 α+sin 2 αcos 2 α) Which of the above is/are identites ?

UPSC CDS I 2025 Mathematics Paper

Question : 22 of 100

Marks: +1, -0

Consider the following:
I − sin ⁡ 6 α = cos ⁡ 2 α ( cos ⁡ 4 α − 3 cos ⁡ 2 α + 3 )
II.cos⁸α−sin⁸α=2sin²α(1−cos⁴α+sin²αcos²α)
Which of the above is/are identites ?

I only
II only
Both I and II
Neither I nor II

Validate

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