Q. The function $f(x) = 1 - x^{3}$
A) Increases everywhere
B) Decreases in $(0,\ \infty)$
C) Increases in $(0,\ \infty)$
D) None of these
Explanation
(b)
Given, $f(x) = 1 - x^{3}$
$f^{'}(x) = - 3x^{2} < 0,\forall x \in R$
So, $f(x)is\ decrease\ in\ ( - \infty,\infty)$
Hence, option (b) is correct.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.