The disk method will only involve a single integral. I've attached a sketch of the bounded region (in red) and one such disk made by revolving it around the y-axis.
Such a disk has radius x = 1/y and height/thickness ∆y, so that the volume of one such disk is
π (radius) (height) = π (1/y)² ∆y = π/y² ∆y
and the volume of a stack of n such disks is

where
is a point sampled from the interval [1, 5].
As we refine the solid by adding increasingly more, increasingly thinner disks, so that ∆y converges to 0, the sum converges to a definite integral that gives the exact volume V,


Answer:
Well, It is but not because..rotation symmetry, and a square has -turn (or 90-degree) rotation symmetry. As you may have already observed, many figures have 180-degree rotation symmetry but no other rotation symmetry. A figure has 180-degree rotation symmetry if it looks the same when turned halfway around...Soo yeah..I think I am right, So sorry if I'm wrong.
Step-by-step explanation:
Answer:
1 : 140
Step-by-step explanation:
Ratio is 30 : 4200
Divide both numbers by 30:-
= 1 : 140 (answer)