Nếu $\displaystyle\displaystyle\int\limits_1^2f(x)\mathrm{\,d}x=5$ thì $\displaystyle\displaystyle\int\limits_2^1\pi f(x)\mathrm{\,d}x$ bằng
$5\pi$ | |
$\dfrac{\pi}{5}$ | |
$-5\pi$ | |
$-\dfrac{\pi}{5}$ |
Chọn phương án C.
$\displaystyle\int\limits_2^1\pi f(x)\mathrm{\,d}x=-\pi\displaystyle\int\limits_1^2f(x)\mathrm{\,d}x=-5\pi$.