적분법

1 부분 적분

$$\begin{array}{rl}& f(x)g(x)=\int f^{\prime }(x)g(x)dx+\int f(x)g^{\prime }(x)dx\\ & \therefore \int f(x)g^{\prime }(x)dx=f(x)g(x)-\int f^{\prime }(x)g(x)dx\end{array}$$