Nếu $\displaystyle\displaystyle\int\limits_{1}^{2}f(x)\mathrm{\,d}x=-2$ và $\displaystyle\displaystyle\int\limits_{2}^{3}f(x)\mathrm{\,d}x=1$ thì $\displaystyle\displaystyle\int\limits_{1}^{3}f(x)\mathrm{\,d}x$ bằng
| $1$ | |
| $-3$ | |
| $-1$ | |
| $3$ |
Chọn phương án C.
$\displaystyle\int\limits_{1}^{3}f(x)\mathrm{\,d}x=\int\limits_{1}^{2}f(x)\mathrm{\,d}x+\int\limits_{2}^{3}f(x)\mathrm{\,d}x=-2+1=-1$.