Nếu \(\int\limits_{1}^{2}{f\left( x \right)\text{d}x=3},\text{ }\int\limits_{2}^{5}{f\left( x \right)\text{d}x=-1}\) thì \(\int\limits_{1}^{5}{f\left( x \right)\text{d}x}\) bằng
Nếu \(\int\limits_{1}^{2}{f\left( x \right)\text{d}x=3},\text{ }\int\limits_{2}^{5}{f\left( x \right)\text{d}x=-1}\) thì \(\int\limits_{1}^{5}{f\left( x \right)\text{d}x}\) bằng
A.2
B.-2
C.3
D.4
* Đáp án
A
* Hướng dẫn giải
\(\,\int\limits_1^5 {f\left( x \right)dx} \,\, = \int\limits_1^2 {f\left( x \right)dx} + \int\limits_2^5 {f\left( x \right)dx} = 3 - 1 = 2\)