Applications Of Derivatives Question 248
Question: $ 2x^{3}+18x^{2}-96x+45=0 $ is an increasing function when
[RPET 1997]
Options:
A) $ x\le -8,,x\ge 2 $
B) $ x<-2,x\ge 8 $
C) $ x\le -2,x\ge 8 $
D) $ 0\le x\le -2 $
Show Answer
Answer:
Correct Answer: A
Solution:
$ f’(x)=6x^{2}+36x-96>0 $ , for increasing
therefore $ f’(x)=(x+8)(x-2)\ge 0 $
therefore $ x\ge 2,\ x\le -8 $ .
BETA
