Question:
Let $f:(\mathrm{a}, \mathrm{b}) \rightarrow \mathbf{R}$ be twice differentiable function such that $f(x)=\int_{a}^{x} g(t)$ dt for a differentiable function $\mathrm{g}(\mathrm{x})$. If $f(\mathrm{x})=0$ has exactly five distinct roots in $(a, b)$, then $g(x) g^{\prime}(x)=0$ has at least:
Correct Option: , 3
Solution:
$f(x)=\int_{a}^{x} g(t) d t$
$f(x) \rightarrow 5$
$f^{\prime}(x) \rightarrow 4$
$g(x) \rightarrow 4$
$g^{\prime}(x) \rightarrow 3$