#1
Im just going through some Maths exam papers, and I've come across a problem that I can't, for the life of me, remember how to do, and I cannot find any of my notes on it.

The graph of y = sin x is plotted between the limits of 0 and pi/2. Basically, the line is rotated 360degrees at a right angle to the x-axis, so it wraps around, and forms a cone, of sorts.

How do you find the volume of the shape?

I apologize if it isn't particularly clear what I'm asking, I can go get the paper, and copy the question out word for word.
#4
the size of the area underneath pi * sin^2 is your answer

i presume you know how to do that
#5
A line rotated at a 360 degree angle?

Wtf is this ****?
Quote by david9d5
You, my friend, win in epic proportions




Quote by sharpshootr55


Man... now I gotta clean my laptop screen.




Quote by ozzyismetal
^That has too much win for me to handle....
I think I need a glass of water and a nap.


#6
Quote by soulflyV
wat


If it was rotated 360 degrees it wouldn't do shit.


wrapped around a cone. i'd imagine.
Ibanez rg350 DX
My precious, my lovely.
#7
Check your formula book, theres a formula with something to do with the integral of the equation and pi
Drive me home Jeeves
#8
Integrate sin²x from 0 to pi/2 and multiply that by pi.
Yamaha RGX 520FZ
Squier Affinitys Strat (customized!)
Johnson 620 Player Acoustic

Boss HM3 hyper metal
Boss CH1 super chorus
Zoom G1X

Peavey Valveking Royal 8
New: Peavey JSX Mini Collosal
#10
you need to form an equation for tha radius of the conical figure that relates to the position on the x-axis....... inegrate this between your limtis and BANG!!!! donksi's........ unless ur problems are different to mine that is...........
Quote by Bubban
I once had a sudden urge to rape sheep in Scotland after watching CNN, that was pretty freaky.
#11
Quote by saphrax
Then divide by 0.


no the person who you quoted was actually right
#12
Could you please copy the question out...

cause if you integrate the curve then u'd get the surface area of the cone and not the volume enclosed by the cone..


ya so copy the question out cause this seems interesting....i'm waitin
Quote by blynd_snyper
yes we all need answers to xboys questions hurry up goddam it


Quote by Kankuro
Damn you X-Boy!!!


Founder And Member Of The " I Don't Masturbate Club "

TURNED 18 TODAY !!! (22/02)
#13
Quote by X-Boy
Could you please copy the question out...

cause if you integrate the curve then u'd get the surface area of the cone and not the volume enclosed by the cone..


ya so copy the question out cause this seems interesting....i'm waitin


the integral of a curve is te area under it so if you rotate it you will get volume
#15
Quote by acdcfan1556
the integral of a curve is te area under it so if you rotate it you will get volume



Ahem ok...

Cut out a n shaped piece of paper...which will be a representation of the curve...


Now if you integrate the area under the curve you get the area of the piece of paper you have...

If you make a cone out of that piece of paper the area of the paper used will not give you the volume of the cone...it'll be the surface area of the cone


See ??
Quote by blynd_snyper
yes we all need answers to xboys questions hurry up goddam it


Quote by Kankuro
Damn you X-Boy!!!


Founder And Member Of The " I Don't Masturbate Club "

TURNED 18 TODAY !!! (22/02)
#16
Quote by X-Boy
Ahem ok...

Cut out a n shaped piece of paper...which will be a representation of the curve...


Now if you integrate the area under the curve you get the area of the piece of paper you have...

If you make a cone out of that piece of paper the area of the paper used will not give you the volume of the cone...it'll be the surface area of the cone


See ??

No, that's not the cone you're looking for. This is a solids of revolution type of question.
You spin the sin curve around the x-axis, making a 3d shape out of that. This is the volume we're looking for.
Yamaha RGX 520FZ
Squier Affinitys Strat (customized!)
Johnson 620 Player Acoustic

Boss HM3 hyper metal
Boss CH1 super chorus
Zoom G1X

Peavey Valveking Royal 8
New: Peavey JSX Mini Collosal
#18
Oh k k....my bad....i thought you were making a cone using the curve.

Yeah i get it...sorry
Quote by blynd_snyper
yes we all need answers to xboys questions hurry up goddam it


Quote by Kankuro
Damn you X-Boy!!!


Founder And Member Of The " I Don't Masturbate Club "

TURNED 18 TODAY !!! (22/02)
#20
Quote by umop-3p!sdn
...I finished the question about an hour and a half ago...

Oh well. Some of the replies we're quite funny (in a really geeky way :/)
Yamaha RGX 520FZ
Squier Affinitys Strat (customized!)
Johnson 620 Player Acoustic

Boss HM3 hyper metal
Boss CH1 super chorus
Zoom G1X

Peavey Valveking Royal 8
New: Peavey JSX Mini Collosal
#22
Quote by acdcfan1556
no the person who you quoted was actually right

Lol, you don't understand maths do you?
United as One, Divided by Zero
#24
Quote by umop-3p!sdn
Im just going through some Maths exam papers, and I've come across a problem that I can't, for the life of me, remember how to do, and I cannot find any of my notes on it.

The graph of y = sin x is plotted between the limits of 0 and pi/2. Basically, the line is rotated 360degrees at a right angle to the x-axis, so it wraps around, and forms a cone, of sorts.

How do you find the volume of the shape?

I apologize if it isn't particularly clear what I'm asking, I can go get the paper, and copy the question out word for word.



you need to integrate (sinx)² between 0 an pi/2, and then multiply it all by pi:

π∫(sinx)²dx

between 0 and π/2, where 0 is the lower limit and π/2 is the upper limit (it would be drawn on the integral sign but i dont know how to do it on the computer).

basically, you integrate (sinx)². then substitute π/2 for x. do the same thing again but this time substitute 0 for x. subtract the second value from the first and you have the volume of the shape.

good luck.
Does anyone remember laughter?

Manuel, please try to understand before one of us DIES.

my gear:

Gibson LP Standard
Epiphone SG
Classical guitar
Peavey ValveKing 112
Marshall MG15
BOSS ME-50