If 15 sin 4 α + 10 cos 4 α = 6 , for some α ∈ R , then the value of 27 sec 6 α + 8…

If 15sin4α+10cos4α=6, for some αR, then the value of 27sec6α+8cosec6α is equal to :
  1. 350
  2. 500
  3. 400
  4. 250

Solution

15sin4α+10cos4α=6

15sin4α+10cos4α=6sin2α+cos2α2

3sin2α-2cos2α2=0

 3sin2α-2cos2α=0

tan2α=23 & cot2α=32

27sec6α+8cosec6α

=27sec2α3+8cosec2α3

=271+tan2α3+81+cot2α3

=271+233+81+323

=250

Asked in: JEE Main 2021 (18 Mar Shift 2)

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