• Want to take part in this year's BoS Trials event for Maths and/or Business Studies?
    Click here for details and register now!
  • YOU can help the next generation of students in the community!
    Share your trial papers and notes on our Notes & Resources page

Integration (1 Viewer)

Lukybear

Active Member
Joined
May 6, 2008
Messages
1,466
Gender
Male
HSC
2010
y=2/(2x-6)

Find the volume of the solid of revolution by rotating the curves around the x axis, x=5, x=6.

Do not get the method of this question. Please help!
 

addikaye03

The A-Team
Joined
Nov 16, 2006
Messages
1,267
Location
Albury-Wodonga, NSW
Gender
Male
HSC
2008
y=2/(2x-6)

Find the volume of the solid of revolution by rotating the curves around the x axis, x=5, x=6.

Do not get the method of this question. Please help!
V=pi int. (y^2) dx where y= 2/2x-6 which =1/(x-3). Therefore y^2=1/(x-3)^2

V=|-pi1/[x-3]|from 5 to 6

pi(1/2-1/3)=pi/6 unit sq
 

Lukybear

Active Member
Joined
May 6, 2008
Messages
1,466
Gender
Male
HSC
2010
O darn. Didnt know recognise the ability to simplify. How stupid.

But what if it was give 5/(2x-6)??
 

annabackwards

<3 Prophet 9
Joined
Jun 14, 2008
Messages
4,670
Location
Sydney
Gender
Female
HSC
2009
O darn. Didnt know recognise the ability to simplify. How stupid.

But what if it was give 5/(2x-6)??
The only thing would be the simplification.
You'd integrate ^2 = 25/4(x-3)^2
Which would equal 25pi/4x6 = 25pi/24
 

Lukybear

Active Member
Joined
May 6, 2008
Messages
1,466
Gender
Male
HSC
2010
O thx so mcuh. Forgot about that identy. O man, im screwed for my tests upcoming.
 

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

Top