Homework SourseLet yfxlnx Determine the volume generated by revolving the a
Let y=f(x)=lnx. Determine the volume generated by revolving the area between y=f(x), y=0 from x=1 to x=2 about the x-axis. You must do this using both the disk method and the cylindrical shell method.
Solution
area of a small disc = r*r dx
: * (lnx)2 dx
: [ x (lnx)2 - 2 [ xlnx - x ] ]
: [ 2 (ln2)2 - 4 ln2 + 4 ] - [ 1 ]
: [ 2 (ln2)2 - 4 ln2 + 3 ] answer !!!!
