Ngân hàng bài tập
B
Nếu $\displaystyle\displaystyle\int\limits_{1}^{3}\left[2f(x)+1\right]\mathrm{\,d}x=5$ thì $\displaystyle\displaystyle\int\limits_{1}^{3}f(x)\mathrm{\,d}x$ bằng
 | $3$ |
 | $2$ |
 | $\dfrac{3}{4}$ |
 | $\dfrac{3}{2}$ |
1 lời giải
Chọn phương án D.
$\begin{aligned}\displaystyle\int\limits_{1}^{3}\left[2f(x)+1\right]\mathrm{\,d}x&=2\displaystyle\int\limits_{1}^{3}f(x)\mathrm{\,d}x+\displaystyle\int\limits_{1}^{3}\mathrm{\,d}x\\ &=2\displaystyle\int\limits_{1}^{3}f(x)\mathrm{\,d}x+2=5.\end{aligned}$
Suy ra $\displaystyle\int\limits_{1}^{3}f(x)\mathrm{\,d}x=\dfrac{3}{2}$.