How do I find the integral intx^5*ln(x)dxx5ln(x)dx ?

1 Answer
Sep 24, 2014

By Integration by Parts,

int x^5lnx dx=x^6/36(6lnx-1)+Cx5lnxdx=x636(6lnx1)+C

Let us look at some details.

Let u=lnxu=lnx and dv=x^5dxdv=x5dx.
Rightarrow du={dx}/xdu=dxx and v=x^6/6v=x66

By Integration by Parts

int udv=uv-int vduudv=uvvdu,

we have

int (lnx)cdot x^5dx=(lnx)cdot x^6/6-int x^6/6cdot dx/x(lnx)x5dx=(lnx)x66x66dxx

by simplifying a bit,

=x^6/6lnx-int x^5/6dx=x66lnxx56dx

by Power Rule,

=x^6/6lnx-x^6/36+C=x66lnxx636+C

by factoring out x^6/36x636,

=x^6/36(6lnx-1)+C=x636(6lnx1)+C