Xác định các điểm parapol
\(f\left(x\right)=\dfrac{2}{3}\left(x^2-4x+3\right)=\dfrac{2}{3}\left(x-1\right)\left(x-3\right)=\dfrac{2}{3}\left(x-2\right)^2-\dfrac{2}{3}\)
\(1< x< 3\Rightarrow f\left(x\right)< 0\)
\(\left[{}\begin{matrix}x\le1\\x\ge3\end{matrix}\right.\) \(\Rightarrow f\left(x\right)\ge0\)
\(\left|f\left(x\right)\right|=\left\{{}\begin{matrix}\left\{{}\begin{matrix}f\left(x\right)\\\left[{}\begin{matrix}x\le1\\x\ge1\end{matrix}\right.\end{matrix}\right.\\-f\left(x\right)khi\left\{1< x< 3\right\}\end{matrix}\right.\)
*. đỉnh GTNN.P(2,-2/3)
.Giao với trục hoành A(1,0); B(3,0)
Giao trục tung C(0,2)
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