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finding volume by integration watch

1. hi, i come across this question but totally have no clue to this one. please give me some hints. thanks

2. (Original post by kingsclub)
hi, i come across this question but totally have no clue to this one. please give me some hints. thanks

Ok, how much do you know about parametric equations and volumes of revoultion?

You'll need to convert the two parametric equations into one Cartesian equation in the form y=....
3. so far i've only learnt how to find volumes of a single equation using disc and shell methods...
4. (Original post by kingsclub)
so far i've only learnt how to find volumes of a single equation using disc and shell methods...
I've never heard of those methods...

If you don't know about parametric equations, then I don't think you'll be able to do this. I'm not entirely sure, though.

(Original post by Farhan.Hanif93)
...
Help?
5. (Original post by Doughnuts!!)
Help?
Somehow, I've never come across integrating the parametric equation of any curve in maths before but I'll try my best.

(Original post by kingsclub)
hi, i come across this question but totally have no clue to this one. please give me some hints. thanks

Have you ever come across the formula for the volume generated by rotating a section of a curve (in cartesian form) completely about the x-axis? I think it'd be similar to dealing with that but instead you'll need to consider:

Someone more knowledgeable, feel free to correct me if I'm wrong on this.
6. As Farhan.Hanif93 said.

Alternatively, eliminate t from your two equations, then get an expression for y^2 from that. You'll need to sort out the limits.

Edit: Actually, my latter suggestion looks rather messy when I look at the details.
7. (Original post by Farhan.Hanif93)
Somehow, I've never come across integrating the parametric equation of any curve in maths before but I'll try my best.
Same. Though I think my hunch about integrating the Cartesian seems to be spot on...
8. (Original post by Doughnuts!!)
Same. Though I think my hunch about integrating the Cartesian seems to be spot on...
Yeah it should work but, as Ghostwalker says, it will probably get messy.

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