Phân tích $I = \int \dfrac{e^x}{e^{2x} -3.e^x +2}dx = \int \dfrac{d(e^x)}{e^{2x} -3.e^x +2} = \int \dfrac{1}{t^2 -3t+2}dt$
$=\int \dfrac{1}{(t-1)(t-2)}dt =\int \bigg (\dfrac{1}{t-2} -\dfrac{1}{t-1} \bigg )dt$
$=\ln|t-2|-\ln |t-1| + C =\ln \bigg | \dfrac{t-2}{t-1} \bigg | +C =\ln \bigg | \dfrac{e^x-2}{e^x-1} \bigg | +C$