Cho hàm số f(x) liên tục trên đoạn

A.\[\mathop \smallint \limits_a^b f\left( x \right)dx = - \mathop \smallint \limits_b^a f\left( x \right)dx\]

B. \[\mathop \smallint \limits_a^b kdx = k\left( {b - a} \right)\]

C. \[\mathop \smallint \limits_a^b f\left( x \right)dx + \mathop \smallint \limits_b^c f\left( x \right)dx = \mathop \smallint \limits_a^c f\left( x \right)dx\]

D. \[\mathop \smallint \limits_a^b f\left( x \right)dx = \mathop \smallint \limits_b^a f\left( { - x} \right)dx\]