Shell Method Question - Where am I wrong?

In summary, the shell method is a mathematical technique used to find the volume of a solid of revolution by integrating the product of the circumference of a shell and its height. It is different from the disk method in that it uses the circumference of a shell and is used when the axis of revolution is parallel to the axis of integration. The formula for the shell method is V = 2π ∫(radius)(height)(thickness) dx, and it can only be used for cylindrical shapes. To ensure correct setup, the axis of revolution should be parallel to the axis of integration and the variables of height and thickness should be properly defined. Another method, such as the disk method, can also be used to verify the results.
  • #1
Bellwether
5
0

Homework Statement



Find the volume of the solid created when the area between the function y=xe0.5x and the x-axis (for 0≤x≤2) is rotated about the line x=-2

Homework Equations



Shell Method: Vs = ∫ 2∏r * f(x)

The Attempt at a Solution



r = x + 2

r * f(x) = x2e0.5x + 2xe0.5x

Thus, 2∏∫ (x2e0.5x + 2xe0.5x)dx {from 0 to 2}

My final answer is 16∏(e1 - 1) ≈ 86.3703

Did I make a mistake somewhere?
 
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  • #2
It looks correct.
 

1. What is the shell method?

The shell method is a mathematical technique used to find the volume of a solid of revolution by integrating the product of the circumference of a shell and its height.

2. How is the shell method different from the disk method?

The shell method is based on the circumference of a shell, while the disk method uses the radius of a disk. Additionally, the shell method is used when the axis of revolution is parallel to the axis of integration, while the disk method is used when the axis of revolution is perpendicular to the axis of integration.

3. What is the formula for the shell method?

The formula for the shell method is V = 2π ∫(radius)(height)(thickness) dx, where the radius is the distance from the axis of revolution to the shell, the height is the function of x, and the thickness is the width of the shell.

4. Can the shell method be used for any shape?

No, the shell method can only be used for finding the volume of solids of revolution that have a cylindrical shape, such as a cone, a cylinder, or a frustum (truncated cone).

5. How do I know if I have set up the shell method correctly?

You can check if you have set up the shell method correctly by making sure that the axis of revolution is parallel to the axis of integration, and that the height and thickness of the shell are correctly defined in terms of the variable of integration. You can also check your answer by using a different method, such as the disk method, to see if you get the same result.

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