MedVision ad

Volumes about the Y-Axis (1 Viewer)

flon

Member
Joined
Feb 17, 2008
Messages
30
Gender
Male
HSC
2010
The curve y=x^3 is rotated about the y-axis from y = 0 to y= 1.

Find the value of the solid formed.

Thanks in advance.
 

GUSSSSSSSSSSSSS

Active Member
Joined
Aug 20, 2008
Messages
1,102
Location
Turra
Gender
Male
HSC
2009
回覆: Volumes about the Y-Axis

y = x^3 --> x = y^(1/3)
volume = piS[f(y)]^2 . dy OR piS[x^2]dy
therefore

volume = pi.S[y^(2/3)]dy ...........limits: 1 --> 0
=pi[(3/5)y^(5/3)] ...........limits: 1 --> 0
=3pi/5
 
Last edited:

Fortify

♪웨딩드레스
Joined
Mar 20, 2007
Messages
1,281
Gender
Male
HSC
2009
You guys forgot to x^2.

V = pi [int] x^2 dy ?
 

Fortify

♪웨딩드레스
Joined
Mar 20, 2007
Messages
1,281
Gender
Male
HSC
2009
x^2 = y ^2/3

V = pi [int] y^2/3 dy with limits of 1 and 0
V = pi [3/5 * y ^ 5/3 ] with limits of 1 and 0
V = pi [3/5 - 0]
V = 3pi/5 units^3
 

jet

Banned
Joined
Jan 4, 2007
Messages
3,148
Gender
Male
HSC
2009
LOL. I can't believe i forgot that!
+ 1.
 

flon

Member
Joined
Feb 17, 2008
Messages
30
Gender
Male
HSC
2010
LOL

dw jetblack i made the same mistake as you. thats why i couldnt get it right.
 

jet

Banned
Joined
Jan 4, 2007
Messages
3,148
Gender
Male
HSC
2009
Ironically, I put x2 in the formula.....
 

Gibbatron

Member
Joined
Mar 20, 2009
Messages
339
Gender
Male
HSC
N/A
In the time it took me to work out how to use the equation editor, everyone else had already posted the answer lol
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top