@perl

Question

@perl

perl · Answer

brb, afk

wade123 · Answer

whats afk?

wade123 · Answer

i just want to see if i got it

anonymous · Answer

hehehe.. I think you don't need help anymore.

wade123 · Answer

yes i do :/

arabpride · Answer

afk = away from keyboard ;P

wade123 · Answer

ohhh hahahha makes sense

anonymous · Answer

@arabpride  can you help? I am not sure about it

arabpride · Answer

I'm not sure either xP i have no idea how i earned my "mathlete" title huehue
sorry 'o'

wade123 · Answer

hahah its ookay(:

wade123 · Answer

@DanJS please help!!

anonymous · Answer

@freckles

anonymous · Answer

Question: if the curve is limited by those lines, it is not a solid, right? only when it rotates about x or y axis, then it is a solid and it has a base to calculate.

anonymous · Answer

To me, the question is quite unclear.

anonymous · Answer

https://www.desmos.com/calculator/azx7njzuu6

freckles · Answer

this is just disk method it seems to me

danjs · Answer

hi , i am back finally

freckles · Answer

$$\int\limits_{0}^{1} \pi (radius)^2 dx$$
radius=e^(-x)

anonymous · Answer

@freckles  but at least, we have to know which axis it rotates about, right?

freckles · Answer

it is being rotated about the x-axis

freckles · Answer

it says so when it says the cross sections are perpendicular to the x-axis

freckles · Answer

as least that is how i translated it

anonymous · Answer

Nope, it say: cross section perpendicular to the x-axis,

freckles · Answer

that is what i just said @OOOPS

anonymous · Answer

not "cross section ARE  perpen......"

danjs · Answer

Right, Half of that, it says semi-circles

freckles · Answer

|dw:1420769170680:dw|
this line segment i drew on @campbell_st 's post is perpendicular to the x-axis