Exact Volume of Solid of Revolution for y=cos(x^2) | Rotating about x and y-Axis

In summary, the problem is to find the exact volume of the solid of revolution obtained by rotating the region in the first quadrant enclosed by the x-axis, y-axis, and the curve y=cos(x^2) about both the x-axis and y-axis. The student is using the method of cylindrical shells or disks and is unsure of the integration limits. The solution will involve determining the volume of a typical volume element and using that as the integrand.
  • #1
seto6
251
0

Homework Statement


let R be the region enclosed by the x-axis,y-axis and the curve y=cos(x^2)
A)find the exact volume of the solid of revolution obtained by rotating R about the y-axis

B) find the exact volume of the solid of revolution obtained by rotating R about the x-axis

i am lost on the integration limit and how to set up this problem help please got exam in 10hours

Homework Equations


The Attempt at a Solution


A) r=X and h= cos(x^2)
so integrate from 0 to infinity of 2 pi (x)(cos(x^2)) dx= pi sin(x^2)<-i don't think this is correct
 
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  • #2
seto6 said:

Homework Statement


let R be the region enclosed by the x-axis,y-axis and the curve y=cos(x^2)
Is this the exact description of the region as shown in your book? A better description might be "the region in the first quadrant enclosed by the x-axis,y-axis and the curve y=cos(x^2)."
seto6 said:
A)find the exact volume of the solid of revolution obtained by rotating R about the y-axis

B) find the exact volume of the solid of revolution obtained by rotating R about the x-axis

i am lost on the integration limit and how to set up this problem help please got exam in 10hours

Homework Equations





The Attempt at a Solution


A) r=X and h= cos(x^2)
so integrate from 0 to infinity of 2 pi (x)(cos(x^2)) dx= pi sin(x^2)<-i don't think this is correct
Where does the graph of y = cos(x^2) cross each axis? For the first problem, are you using cylindrical shells or disks? Same for the second problem. I can tell which method you are using, but you should say what method you're using as part of the work you do.

For each integral, what's the volume of your typical volume element? That will correspond directly to your integrand.
 
  • #3
thanks a lot man it makes more sense now
ps: this question was from a previous exam i was not given any grap or any thing

i got it now thanks again
 

What is the formula for finding the exact volume of a solid of revolution for y=cos(x^2) when rotated about the x-axis?

The formula for finding the exact volume of a solid of revolution for y=cos(x^2) when rotated about the x-axis is V = π∫a^b (cos(x^2))^2 dx, where a and b are the limits of integration.

What is the formula for finding the exact volume of a solid of revolution for y=cos(x^2) when rotated about the y-axis?

The formula for finding the exact volume of a solid of revolution for y=cos(x^2) when rotated about the y-axis is V = 2π∫a^b x(cos(x^2)) dx, where a and b are the limits of integration.

What is the process for finding the limits of integration for y=cos(x^2) when rotating about the x-axis?

To find the limits of integration for y=cos(x^2) when rotating about the x-axis, set the equation equal to 0 and solve for x. The values of x where cos(x^2) = 0 will be the limits of integration. Use a graphing calculator or software to help visualize the graph and determine the limits.

Can the same formula be used for any function when finding the volume of a solid of revolution?

No, the formula for finding the volume of a solid of revolution will vary depending on the function and the axis of rotation. It is important to carefully consider the shape and symmetry of the function to determine the correct formula to use.

What is the significance of using the exact volume formula instead of an approximation?

The exact volume formula allows for a more precise calculation of the volume of a solid of revolution. This is especially important in scientific research where accuracy is crucial. It also allows for a better understanding of the shape and properties of the solid being rotated.

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