Nếu $\int_{0}^{2}{f\left(x \right)dx=3}$ và $\int_{0}^{5}{f\left(x \right)dx=6}$ thì $\int_{2}^{5}{f\left(x \right)dx}$ bằng

Ta có $\int_{0}^{5}{f\left(x \right)dx=\int_{0}^{2}{f\left(x \right)dx+\int_{2}^{5}{f\left(x \right)dx\Rightarrow \int_{2}^{5}{f\left(x \right)dx=\int_{0}^{5}{f\left(x \right)dx-\int_{0}^{2}{f\left(x \right)dx=6-3}=3}}}}}$.
Vậy $\int_{2}^{5}{f\left(x \right)dx=3}$.