Question

Through cylindrical shells to find the volume of the solid generated by revolving the region enclosed by the graphs of y=e^x/2,y=1, x=ln3 about x axix

Answer 1

If you mean y = e^(x/2) then the graphs intersect at a=(0,1) and b=(ln3,√3)
If you mean y = (e^x)/2 then the intersections are at a=(ln3,3/2) and b=(ln2,1)
In any case, you want
∫ 2πrh dy
where h is the horizontal "height" of the cylinders and r=y