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Question: Answered & Verified by Expert
Let x denote the fractional part of x and fx=cos11x2sin11xxx3,x0. If L and R respectively denotes the left hand limit and the right hand limit of fx at x=0, then 32π2L2+R2 is equal to __________.
MathematicsLimitsJEE MainJEE Main 2024 (01 Feb Shift 1)
Solution:
2920 Upvotes Verified Answer
The correct answer is: 18

Given: fx=cos11x2sin11xxx3

RHL=limx0+fx=limh0f0+h

RHL=limh0fh

RHL=limh0cos11h2sin11hh1h2

RHL=limh0cos11h2hsin111

Let cos11h2=θcosθ=1h2

RHL=π2limθ0θ1cosθ

RHL=π2limθ011cosθθ2

RHL=π2112

RHL=π2

R=π2

Now finding left hand limit,

LHL=limx0fx

LHL=limh0fh

LHL=limh0cos11h2sin11hhh3

LHL=limh0cos11h+12sin11h+1h+1h+13

LHL=limh0cos1h2+2hsin1h1h11h2

LHL=limh0π2sin1h11h2

LHL=π2limh0sin1hh2+2h

LHL=π2limh0sin1hh1h+2

LHL=π4

L=π4

32π2L2+R2=32π2π22+π216

32π2L2+R2=16+2

32π2L2+R2=18

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