$\int_1^2 \dfrac{1}{x(x^{10}+1)^2}dx=\int_1^2 \dfrac{x^9}{x^{10}(x^{10}+1)^2}dx$đặt $x^{10}+1 = t \Rightarrow 10x^9 dx = dt$$I = \dfrac{1}{10}\int \dfrac{1}{(t-1).t^2}dt =\dfrac{1}{10} \int \bigg (-\dfrac{1}{t^2}-\dfrac{1}{t}+\dfrac{1}{t-1} \bigg )dt$em tự làm nốt nhé !
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I=\int_1^2 \dfrac{1}{x(x^{10}+1)^2}dx=\int_1^2 \dfrac{x^9}{x^{10}(x^{10}+1)^2}dx$đặt $x^{10}+1 = t \Rightarrow 10x^9 dx = dt$$I = \dfrac{1}{10}\int \dfrac{1}{(t-1).t^2}dt =\dfrac{1}{10} \int \bigg (-\dfrac{1}{t^2}-\dfrac{1}{t}+\dfrac{1}{t-1} \bigg )dt$em tự làm nốt nhé !