1. $ I_1 = \int_{-\propto }^{+\propto }\frac{dx}{(x-1)(x^2+1)} $
2. $ I_2 = \int_{-\propto }^{+\propto }\frac{e^{ix}dx}{x(x^2+4)^2}$
3. $ I_3 = \int_{-\propto }^{+\propto }\frac{x^2dx}{(x^2+a^2)(x^2+b^2)} (a,b>0) $
4. $ I_4 = \int_{-\propto }^{+\propto }\frac{dx}{x^5+1}$
5. $ I_5 = \int_{0 }^{2\pi }\frac{cos2xdx}{1-2acosx+a^2} (\mid a\mid <1) $
