Cho \(\displaystyle\int\limits_{0}^{1}f(x)\mathrm{\,d}x=-1\), \(\displaystyle\int\limits_{0}^{3}f(x)\mathrm{\,d}x=5\). Tính \(\displaystyle\int\limits_{1}^{3}f(x)\mathrm{\,d}x\).
\(5\) | |
\(4\) | |
\(1\) | |
\(6\) |
Chọn phương án D.
Bằng cách tách cận ta có $$\begin{eqnarray*}
&\displaystyle\int\limits_{0}^{3}f(x)\mathrm{\,d}x&=\displaystyle\int\limits_{0}^{1}f(x)\mathrm{\,d}x+\displaystyle\int\limits_{1}^{3}f(x)\mathrm{\,d}x\\
\Leftrightarrow&5&=-1+\displaystyle\int\limits_{1}^{3}f(x)\mathrm{\,d}x\\
\Leftrightarrow&6&=\displaystyle\int\limits_{1}^{3}f(x)\mathrm{\,d}x.
\end{eqnarray*}$$