Application of Derivatives — Maths STD 12 Science — Question
Gujarat BoardEnglish MediumSTD 12 ScienceMathsApplication of Derivatives1 Mark
MCQ
The function $f(x)=1-x^3-x^5$ is decreasing for
A
$1 \leq x \leq 5$
B
$x \leq 1$
C
$x \geq 1$
✓
all values of $x$
✓
Answer
Correct option: D.
all values of $x$
(d) : Given, $f(x)=1-x^3-x^5$ Differentiating w.r.t. $x$, we get $ f^{\prime}(x)=-3 x^2-5 x^4 $ $\Rightarrow f^{\prime}(x)=-\left(3 x^2+5 x^4\right) \Rightarrow f^{\prime}(x)<0$ for all values of $x$.
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