Download the app

Questions  

 If g(x)=2f2x33x2+f6x24x33,xR and f′′(x)>0,xR, then g(x) is incresing in

a
−∞,−12∪0,1
b
−12,0∪1,∞
c
0,∞
d
−∞,1

detailed solution

Correct option is B

For g(x) to be increasing function g′(x)>0,∀x Since f′′(x)>0⇒f′(x) is increasing function  Now, g(x)=2f2x3−3x2+f6x2−4x3−3g′(x)=26x2−6xf′2x3−3x2+12x−12x2f′6x2−4x3−3g′(x)=12x(x−1)f′2x3−3x2−f′6x2−4x3−3>0 case 1:if f′2x3−3x2>f′6x2−4x3−3⇒2x3−3x2>6x2−4x3−3∵f′(x) is increases ⇒2x3−3x2+1>0⇒(x−1)2(2x+1)>0  ⇒x>-12∴g′(x)>0 ⇒x(x−1)>0 and (2x+1)>0∴g(x) is increasing on −12,0∪(1,∞)  case 2:if f′2x3−3x20

Talk to our academic expert!

+91

Are you a Sri Chaitanya student?


Similar Questions

If f′′(x)>0xR,f(3)=0, and g(x)=ftan2x2 tanx+4,0<x<π2, then g(x) is increasing in


phone icon
whats app icon