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Câu hỏi: Nếu $\int\limits_{0}^{m}{\left( 2x-1 \right)dx}=2$ thì $m$ có giá trị bằng
A. $\left[ \begin{aligned}
& m=1 \\
& m=-2 \\
\end{aligned} \right.. $
B. $ \left[ \begin{aligned}
& m=1 \\
& m=2 \\
\end{aligned} \right.. $
C. $ \left[ \begin{aligned}
& m=-1 \\
& m=-2 \\
\end{aligned} \right.. $
D. $\left[\begin{array}{l}m=-1 \\ m=2\end{array}\right.$
A. $\left[ \begin{aligned}
& m=1 \\
& m=-2 \\
\end{aligned} \right.. $
B. $ \left[ \begin{aligned}
& m=1 \\
& m=2 \\
\end{aligned} \right.. $
C. $ \left[ \begin{aligned}
& m=-1 \\
& m=-2 \\
\end{aligned} \right.. $
D. $\left[\begin{array}{l}m=-1 \\ m=2\end{array}\right.$
Ta có $\int\limits_{0}^{m}{\left( 2x-1 \right)dx}=2$
$\Rightarrow \left( {{x}^{2}}-x \right)\left| \begin{aligned}
& m \\
& 0 \\
\end{aligned} \right.=2\Leftrightarrow {{m}^{2}}-m=2\Leftrightarrow \left[ \begin{aligned}
& m=2 \\
& m=-1 \\
\end{aligned} \right..$
$\Rightarrow \left( {{x}^{2}}-x \right)\left| \begin{aligned}
& m \\
& 0 \\
\end{aligned} \right.=2\Leftrightarrow {{m}^{2}}-m=2\Leftrightarrow \left[ \begin{aligned}
& m=2 \\
& m=-1 \\
\end{aligned} \right..$
Đáp án D.