Applications Of Derivatives Question 31
Question: For which value of x, the function $ f(x)=x^{2}-2x $ is decreasing
[BIT Ranchi 1990]
Options:
A) $ x>1 $
B) $ x>2 $
C) $ x<1 $
D) $ x<2 $
Show Answer
Answer:
Correct Answer: C
Solution:
$ f(x)={{(x-1)}^{2}}-1 $ .
Hence decreasing in x < 1. Aliter : $ f’(x)=2x-2=2(x-1) $ To be decreasing, $ 2(x-1)<0\Rightarrow (x-1)<0\Rightarrow x<1 $ .
BETA
