RD Sharma - Mathematics (Volume 1)

Book: RD Sharma - Mathematics (Volume 1)

Chapter: 17. Increasing and Decreasing Functions

Subject: Maths - Class 12th

Q. No. 12 of MCQ

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12

Mark the correct alternative in the following:

Function f(x) = cosx – 2λ x is monotonic decreasing when


Formula:- (i) The necessary and sufficient condition for differentiable function defined on (a,b) to be strictly decreasing on (a,b) is that f’(x)<0 for all x(a,b)


Given:-


f(x) = cosx – 2λ x


=-sinx-2λ =f’(x)


for decreasing function f’(x)<0


-sinx-2λ <0


Sinx+2λ >0


2λ>-sinx


2λ>1


1

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