Nếu \(\int\limits_{ – 1}^3 {f\left( x \right){\rm{d}}x = 2} \) thì \(\int\limits_{ – 1}^3 {\left[ {2x – f\left( x \right)} \right]{\rm{d}}x} \) bằng

Câu hỏi:
Nếu \(\int\limits_{ – 1}^3 {f\left( x \right){\rm{d}}x = 2} \) thì \(\int\limits_{ – 1}^3 {\left[ {2x – f\left( x \right)} \right]{\rm{d}}x} \) bằng

A. \(6\).

B. \(8\).

C. \(10\).

D. \(12\).

GY:

Ta có: \(\int\limits_{ – 1}^3 {\left[ {2x – f\left( x \right)} \right]{\rm{d}}x} = 2\int\limits_{ – 1}^3 {x{\rm{d}}x – \int\limits_{ – 1}^3 {f\left( x \right){\rm{d}}x} } = 8 – 2 = 6.\)

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