Let … be defined as … Let A = {x … R : f is increasing}. Then A is equal to :

Option C. …f(x) = \left\{ {\matrix{ { - 55x,} & {if\,x 4,} \cr

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Application of Derivatives

JEE Main 2021 · 24 Feb, Evening shift · Q2717

MathematicsMedium175×since 2002Q2717

Let

f:R \to R

be defined as

f(x) = \left\{ {\matrix{ { - 55x,} & {if\,x < - 5} \cr {2{x^3} - 3{x^2} - 120x,} & {if\, - 5 \le x \le 4} \cr {2{x^3} - 3{x^2} - 36x - 336,} & {if\,x > 4,} \cr } } \right.

Let A = {x

\in

R : f is increasing}. Then A is equal to :

JEE Main 2021 · 24 Feb, Evening shift · Q2717

MathematicsMedium175×since 2002Q2717

Let

f:R \to R

be defined as

f(x) = \left\{ {\matrix{ { - 55x,} & {if\,x < - 5} \cr {2{x^3} - 3{x^2} - 120x,} & {if\, - 5 \le x \le 4} \cr {2{x^3} - 3{x^2} - 36x - 336,} & {if\,x > 4,} \cr } } \right.

Let A = {x

\in

R : f is increasing}. Then A is equal to :