Cylindrical shells trouble integrating

In summary, cylindrical shells are a method of integration used to find the volume of a solid with a circular cross-section. It involves dividing the solid into thin, vertical slices and integrating the product of the circumference and height of each slice. While some people may have trouble using this method due to its reliance on calculus and visualization skills, there are tips for successfully solving problems involving cylindrical shells, such as carefully drawing and labeling the solid and paying attention to units and limits of integration. It is important to avoid common mistakes, such as using the wrong formula or limits of integration, when using cylindrical shells for integration.
  • #1
ACLerok
194
0
i'm told to use the method of cylindrical shells to find the volume gnerated by rotating the region bounded these curves about the y axis:
y=e^(-x^2)
y=0
x=0
x=1
Couple questions. What does the graph of y=e^(-x^2) look like? Also, i know the integral is =integral(a,b) 2(pi)x*e^(-x^2) how do i evaulate the e^(-x^2) part?
 
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  • #2
The graph of e-x^2 is the famous "Bell shaped curve"!

As far as the integral of x e-x^2 is concerned, try the substitution u= -x^2.
 
  • #3


The graph of y=e^(-x^2) is a bell-shaped curve that decreases rapidly as x increases. It is also known as a Gaussian curve or a normal distribution curve.

To evaluate the integral of e^(-x^2), you can use the substitution method. Let u=-x^2, then du=-2x dx. Substitute these into the integral to get:
integral(a,b) 2(pi)x*e^(-x^2) dx = integral(a,b) 2(pi) ue^u du
This can now be evaluated using the power rule for integrals. Once you have the antiderivative, you can substitute back in for u and evaluate the integral from a to b. Alternatively, you can use a calculator or a software program to evaluate the integral numerically.
 

1. What are cylindrical shells in the context of integration?

Cylindrical shells refer to the method of integration used to find the volume of a solid with a circular cross-section, such as a cylinder. It involves dividing the solid into thin, vertical slices and integrating the product of the circumference and height of each slice.

2. Why do people have trouble integrating using cylindrical shells?

Some people may have trouble with this method of integration because it requires a solid understanding of calculus and the ability to visualize and manipulate three-dimensional objects. It may also be challenging to set up the integral correctly and determine the limits of integration.

3. Can cylindrical shells be used for any shape?

No, cylindrical shells can only be used for solids with a circular cross-section. For other shapes, other methods of integration, such as the disk method or the washer method, may be more appropriate.

4. What are some tips for solving problems involving cylindrical shells?

Some tips for solving problems using cylindrical shells include carefully drawing and labeling the solid, setting up the integral correctly, and paying attention to the limits of integration. It may also be helpful to practice with simpler examples before tackling more complex problems.

5. Are there any common mistakes to avoid when using cylindrical shells for integration?

Yes, some common mistakes to avoid when using cylindrical shells include using the wrong formula, using the wrong limits of integration, and not properly accounting for units of measurement. It is also important to double-check the setup of the integral and any calculations made during the problem-solving process.

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