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Question

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chris215 · Answer

Volume = (1/2) (4/3) pi r^3

ijlal · Answer

x^2+y^2=r^2 and r=4 so i guess V=(1/2)(4/3)pi(4)^3

ijlal · Answer

not sure though ! but i guess the radius would be 4 since x^2+y^2=r^2 where r is the radius

chris215 · Answer

thats wht i thought

chris215 · Answer

(2/3) pi (4^3)

chris215 · Answer

128pi/3 .. but i think its wrong bc it's not answer choice

irishboy123 · Answer

https://www.wolframalpha.com/input/?i=4+*+integrate+-4+to+4+(16+-+y%5E2+)+dy

irishboy123 · Answer

is that on list?

ijlal · Answer

Can you mention the answer choices ? @chris215

irishboy123 · Answer

because it should look like this https://gyazo.com/4d25fb1db8e63c5db1fb109c30714c44

chris215 · Answer

256/3
	1024π
	16/3
	1024/3

chris215 · Answer

@IrishBoy123 it's not :/

ijlal · Answer

@IrishBoy123  is correct he gave the answer 1024/3 and its the 4th choice you mentioned

ijlal · Answer

@chris215  check again he is correct his answer is your 4th choice !

irishboy123 · Answer

tx @ijlal 

here, you can build a new function $A(y)$  which gives the x-sect area of the solid at any point on the y axis.  

So, as the x-sect at a given y is square: 

$A(y) = l*l = 2 \sqrt{16- y^2} * 2 \sqrt{16- y^2}  = 4 (16 - y^2)$

hence the integral in the MW link

ijlal · Answer

@IrishBoy123  can i ask a thing why couldn't we got with this?
$$v=\pi \int\limits_{-4}^{4}x^2 dy $$

ijlal · Answer

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