simple integral

\hspace{-16}(1)\;\; \int\frac{x^3}{(1+x^3)^2}dx\\\\\\ (2)\;\; \int\frac{2012x-1}{e^{2012x}-2011x}dx

3 Answers

71
Vivek @ Born this Way ·

1.

Again it's getting lengthy. A very complicated use of partial fraction has to be made I guess.

I could complete it till here:

I = ∫dx(1+x)(1-x+x2) -∫dx(1+x)2(1-x+x2)2
I1 I2

I could evaluate I1 by Partial fractions. But Didn't try for I2.

Anyone to complete this or via other method.

1708
man111 singh ·

\hspace{-16}\int\frac{x^3}{(1+x^3)^2}dx$\\\\\\ $\frac{1}{3}.\int x.\frac{3x^2}{(1+x^3)^2}dx$\\\\ Now Using Integration by parts, We Get\\\\ $-\frac{1}{3}.x.\frac{1}{(1+x^3)}+\frac{1}{3}.\int\frac{1}{1+x^3}dx$\\\\

71
Vivek @ Born this Way ·

Very Nice.

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