Applications Of Derivatives Question 270
Question: The function $ f(x)=1-x^{3}-x^{5} $ is decreasing for
[Kerala (Engg.) 2002]
Options:
A) $ 1\le x\le 5 $
B) $ x\le 1 $
C) $ x\ge 1 $
D) All values of x
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Answer:
Correct Answer: D
Solution:
$ f(x)=1-x^{3}-x^{5} $
therefore $ {f}’(x)=-3x^{2}-5x^{4} $
$ {f}’(x)<0 $ for all values of x.