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Question: Answered & Verified by Expert
If the solution of the equation logcosxcotx+4logsinxtanx=1, x0,π2 is sin-1α+β2, where α,β are integers, then α+β is equal to:
MathematicsBasic of MathematicsJEE MainJEE Main 2023 (30 Jan Shift 1)
Options:
  • A 3
  • B 5
  • C 6
  • D 4
Solution:
2518 Upvotes Verified Answer
The correct answer is: 4

Given:

logcosxcotx+4logsinxtanx=1, x0,π2

lncosx-lnsinxlncosx+4lnsinx-lncosxlnsinx=1

1-lnsinxlncosx+41-lncosxlnsinx=1

lnsinxlncosx+4lncosxlnsinx-4=0

(lnsinx)2-4(lnsinx)(lncosx)+4(lncosx)2=0

lnsinx-2lncosx2=0

lnsinx=2lncosx

lnsinx=lncos2x

cos2x=sinx

1-sin2x=sinx

sin2x+sinx-1=0

sinx=-1+52

So, α=-1, β=5

α+β=4

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