Applications Of Derivatives Question 334
Question: The function $ x^{4}-4x $ is decreasing in the interval
Options:
A) [-1, 1]
B) $ (-\infty ,1) $
C) $ [1,+\infty ) $
D) None of these
Show Answer
Answer:
Correct Answer: B
Solution:
Let $ f(x)=x^{4}-4x\Rightarrow f’(x)=4x^{3}-4 $
So, $ 4x^{3}-4<0 $ or $ x^{3}<1 $
Hence function of decreasing in $ (-\infty ,1) $ .
BETA
