Answer
See the explanation below.
Work Step by Step
An inflection point on a curve can be defined as a point of inflection $[c, f(c)]$ that attains a tangent line where we can see that the concavity changes in the graph of a function $f(x)$.
$\underline{Significance}$:
1. When $f'' (x) \gt 0$ on an interval $[m,n]$, then a function $f(x)$ is concave up on that interval.
2. When $f'' (x) \lt 0$ on an interval$[a,b]$, then a function $f(x)$ is concave down on that interval.
3. At a point $x = c$, when $f'' (x)$ changes sign either from positive to negative, or from negative to positive, there exists an inflection point.
