Question

99 POINT QUESTION PLUS BRAINLIEST!!!

Answer 1

Yay, I like das stuff


I think I learned the washer method
goes like this


$area=\pi \int\limits^a_b {(outercurve)^2-(innercurve)^2} \, dx$

ok, so

actuallly, this is easier

y=49-x^2 and
y=0
see when they intersect again
they intersect at -7 and 7
if we do integrate from -7 to 7, then it wil give 0 (because integration is area under the curve), so note that they are same both sides so integrate from 0 to 7 then double the volume to get both sides
so it can't be C or D
It also can'nt be A because it should not be multipied by 4, it should be multipied by 2


basically, we don't need the washer method
remember, area=pir^2
the disk method then
we are summing up all the radii disks and squareing them
but doubleing them so
$area=2\pi (\int\limits^7_0 {49-x^2} \, dx )^2$
no idea why we need the inside part to be x(49-x^2), that is intersting