Nếu $\displaystyle\displaystyle\int\limits_{-1}^2f(x)dx=1$ và $\displaystyle\displaystyle\int\limits_{2}^3f(x)dx=3$ thì $\displaystyle\displaystyle\int\limits_{-1}^3f(x)dx$ bằng
| $2$ | |
| $1$ | |
| $3$ | |
| $4$ |
Chọn phương án D.
Ta có $\displaystyle\int\limits_{-1}^3f(x)\mathrm{d}x=\displaystyle\int\limits_{-1}^2f(x)\mathrm{d}x+\displaystyle\int\limits_{2}^3f(x)\mathrm{d}x=4$.