INTEGRAL CALCULUS QUESTION: I think i finally got the circular disk method down...but can someone show me the formula for the washer and how to use that formula? no drawings needed..:)

Question

inkyvoyd · Answer

loool, who els explained the disk method to you:?

lgbasallote · Answer

lool :p thanks @inkyvoyd haha

amistre64 · Answer

what does a washer look like?

lgbasallote · Answer

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like that? i think it's also known as circular ring right?

amistre64 · Answer

good, and how would you find the area of the ring part?

lgbasallote · Answer

i would say area of the larger circle minus area of the smaller circle..

amistre64 · Answer

good; 

pi(R^2-r^2) is your formula then for each washer you come across

lgbasallote · Answer

i see...so is this just like circular disk? but "twice the fun"?

amistre64 · Answer

yep

inkyvoyd · Answer

No, half the fun, because you do it twice

lgbasallote · Answer

well uhmm when do i use it?

amistre64 · Answer

when you want to know the volume of rotation that has the center missing ...

lgbasallote · Answer

i think its graph does not touch the axis of revolution right? so how do i know when to use that or the cylindrical shell?

amistre64 · Answer

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