Calculating Volume using Integrals
Key Questions

Since its crosssections are squares, its area can be expressed as
#A(y)=(lny)^2#
So, the volume of the solid can be found by:
#V=int_1^{ln4}(lny)^2dy# .
Can you go from here? You might have to use integration by parts twice.
Please watch these videos for more details.