(a) using shells,
v = ∫[1,3] 2πrh dx
where r = x+2 and h=y=ln(x)
using discs,
v = ∫[0,ln3] π(R^2-r^2) dy
where R=5 and r=x+2=2+e^y
(b) use the same ideas with a horizontal axis. Just keep in mind the volume of a disc (or a washer with a hole inside) and a cylinder. I usually try to do it both ways to make sure the answers agree.
Let R be the region bounded by y = ln x, x-axis, and x = 3. Answer the following.
a) Write, but do not solve, an integral expression that will find the volume of the solid that results from rotating R about x = -2.
b) Write, but do not solve, an integral expression that will find the volume of the solid that results from rotating R about y = 4.
I am confused about this question as well. Could you please help me understand how to do this? I would greatly appreciate it!
1 answer
1 answer