For each <em>x</em> in the interval 0 ≤ <em>x</em> ≤ 5, the shell at that point has
• radius = 5 - <em>x</em>, which is the distance from <em>x</em> to <em>x</em> = 5
• height = <em>x</em> ² + 2
• thickness = d<em>x</em>
and hence contributes a volume of 2<em>π</em> (5 - <em>x</em>) (<em>x</em> ² + 2) d<em>x</em>.
Taking infinitely many of these shells and summing their volumes (i.e. integrating) gives the volume of the region:
Area = 7(x + 2) = 7x + 14
Perimeter = 2(7 + x + 2) = 2(9 + x) = 18 + 2x
7x + 14 > 18 + 2x
7x - 2x > 18 - 14
5x > 4
x > 4/5
Because this shape has 2 right angles, we can confirm that it has one set of parallel sides and is a trapezoid. Therefore, use the formula for area of a trapezoid, .5(b1+b2)(h)
.5(1+6)(12)
.5(7)(12)
42 units^2
Answer:
0.5 I think. because for every 2 on the x axis, it grows 1 on the y axis.