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Question: Answered & Verified by Expert
If 4sin2xsin4x+sin2x=3, then x=
MathematicsTrigonometric EquationsAP EAMCETAP EAMCET 2019 (21 Apr Shift 2)
Options:
  • A 2nπ3±π9, nZ
  • B mπ3±π9, nZ
  • C nπ3+(-1)nπ9, nZ
  • D nπ3+(-1)n2π9, nZ
Solution:
1941 Upvotes Verified Answer
The correct answer is: mπ3±π9, nZ

Simplify the given expression

4sin2xsin4x+sin2x=3

2(cos2x-cos6x)+2(1-cos2x)=3

2cos2x-2cos6x+2-2cos2x=3

-2cos6x+2=3

cos6x=-12

Therefore, 6x=2πn±2π3

x=2nπ6±26×π3

x=nπ3±π9

 

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