Nếu $\displaystyle\displaystyle\int\limits_{1}^{3}f(x)\mathrm{\,d}x=2$ thì $\displaystyle\displaystyle\int\limits_{1}^{3}[f(x)+2x]\mathrm{\,d}x$ bằng
| $20$ | |
| $10$ | |
| $18$ | |
| $12$ |
Chọn phương án B.
$\displaystyle\int\limits_{1}^{3}[f(x)+2x]\mathrm{\,d}x=\displaystyle\int\limits_{1}^{3}f(x)\mathrm{\,d}x+\displaystyle\int\limits_{1}^{3}2x\mathrm{\,d}x=2+8=10$