Cho intlimits_0^2 {f(x)dx = 3.} Tính I = intlimits_0^2 {left[ {4f(x) - 3} ight]dx.}

* Hướng dẫn giải

Ta có: 

\(\begin{array}{*{20}{l}}
\begin{array}{l}
I = \int\limits_0^2 {\left[ {4f(x) - 3} \right]dx} \\
= 4\int\limits_0^2 {f(x)dx - 3} \int\limits_0^2 {dx} 
\end{array}\\
{ = \left. {4.3 - 3x} \right|_0^2 = 12 - 6 = 6.}
\end{array}\)