Let f x = 2 x + tan - 1 x and g x = log e 1 + x 2 + x ,   x ∈ 0 , 3 . Then

Let fx=2x+tan-1x and gx=loge1+x2+x, x0,3. Then
  1. There exists x0,3 such that f'x<g'x
  2. max fx>max gx
  3. There exist 0<x1<x2<3 such that fx<gx, xx1,x2
  4. min f'x=1+max g'x

Solution

Given:

fx=2x+tan-1x

f'x=2+11+x2

And,

gx=ln1+x2+x

g'x=11+x2

Now,

0x3

0x29

11+x210

So,

11011+x21

2+1102+11+x23

2+110f'x3

2110f'x3

And,

110g'x1

So, min f'x=21101+max g'x

Option 4 is incorrect

From above,

g'x<f'xx0,3

Option 1 is incorrect.

Since, f'x and g'x are both positive so fx and gx both are increasing

So,

maxfx at x=3 is 6+tan-13

maxgx at x=3 is ln3+10 

And, 6+tan-13>ln3+10 

Option 2 is correct

Asked in: JEE Main 2023 (01 Feb Shift 1)

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