How do you integrate 4xlnx2dx using integration by parts?

1 Answer
Jan 11, 2016

udv=2x2(lnx21)

Explanation:

The Integration by Parts formula is shown by;

udv=uvvdu

To choose u and dv, there are several things to be considered;

  1. dx should be part of dv.
  2. dv should be readily integrated.
  3. u becomes simpler when differentiated.
  4. vdu should be simpler than udv.

When answering this type of question, ensure that u choosen can usually differentiates to zero, while dv is easy to integrate.

Also, choose u in this order;
LIPET : L ogs, I nverse trig., P olynomial, E xponential, T rig.

In this question;
Let u=lnx2 and dv=4xdx
Then, du=2xdx and v=2x2

Using Integration by Parts formula;

udv=uvvdu

udv=lnx2(2x2)(2x2)(2x)dx

udv=lnx2(2x2)4xdx

udv=lnx2(2x2)2x2

udv=2x2(lnx2(1)1)

udv=2x2(lnx21)