Isabel☺
R is bounded by y=0 & y= 4 - x^2 .
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Isabel☺
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suppose it is a parabola:
|dw:1359970089368:dw|
Isabel☺
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@apoorvk
Isabel☺
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@Callisto
Callisto
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What is the question?
Isabel☺
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solve the problem using Disk Method of Solution. Solid V is generated by revolving the given below region R about the x-axis. Draw R and make a sketch of V:
R is bounded by y=0 & y= 4 - x^2 .
Isabel☺
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solve for volume
|dw:1359970762069:dw|
@Callisto
Callisto
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Disk method:
|dw:1359988516003:dw|
\[V = \pi \int_a^b r^2 dx = \pi \int_a^by^2dx\]
To find a and b, solve the equations y=0 & y= 4 - x^2. (The x values you get will be the value of a and b)
\[y=4-x^2\]
Can you do it now?
Isabel☺
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a=0 b=4?
Isabel☺
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can it be like:
|dw:1359971017830:dw|
Callisto
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No....
Solve y=0 and y= 4-x^2
=> y = 0 = 4-x^2
So, now, you need to solve 4-x^2 =0 to find a and b.
Isabel☺
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oh yea right im confused wait...
Callisto
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^That no was for your first question.
You can draw r there.. It doesn't matter where you put the r... since the value of r will be represented by the function y.
Callisto
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Can you solve a quadratic question?
Isabel☺
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x= -2 and +2?
Callisto
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Yes. So, the integral is
\[V = \pi \int_{-2}^{2} y^2 dx=\pi \int_{-2}^{2} (4-x^2)^2 dx\]Can you do it?
Isabel☺
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maybe wait...
Isabel☺
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32 pi/ 3?
Callisto
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Not quite...
Isabel☺
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oh i forgot to square...
Isabel☺
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512pi/ 15?
Callisto
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Yup :)
Isabel☺
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yey! thank you!! :)
Callisto
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You're welcome :)
Hope that you know how to do it now!
Isabel☺
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hopefully yes :) thanks again :)