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Prove that,

101x(1+x).ln[11+x(1+x)]dx=

43(1+122+132+142+........terms)

The given integral =01ln(1+x+x2)x(1+x)dx

=01ln(1+x+x2)1+xdx01ln(1+x+x2)xdx

=01ln[1+(1x)+(1x)2]1+(1x)dx01ln(1+x+x2)xdx

=01ln(1+x+x2)xdx01ln(1+x+x2)xdx

=201ln(1+x+x2)xdx

=201ln(1x)(1+x+x2)(1x)xdx

=201ln(1x)(1x3)xdx

=201ln(1x)xdx201ln(1x3)xdx ......(*)

Consider, I=01ln(1x3)xdx 

Let, x3=t

3x2dx=dt

dxx=dt3x3=dt3t

So, I=01ln(1t)3tdt

I can also be written as 01ln(1x)3xdx

From (*), the given integral

=201ln(1x)xdx201ln(1x)3xdx

=4301ln(1x)xdx

=4301xx22x33x44........xdx

=43011+x2+x23+x34+.........dx

=43(x+x222+x332+x442+..........)|01

=43[0(1+122+132+142+.........)]

=43(1+122+132+142+.........)

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