What Is the Volume of the Object Described by These Triple Integral Limits?

In summary, the given problem can be solved by converting it into cylindrical coordinates and evaluating the integral. However, the answer provided is not entirely correct as the limits of integration for r were not taken into account. Additionally, it may be helpful to interpret the integral as the volume of a solid object to check the solution.
  • #1
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Homework Statement



http://img12.imageshack.us/img12/7181/integral.th.jpg

Homework Equations


The Attempt at a Solution



Well my first attempt is to convert this to a cylindrical coordinate first, which I believed to be:

[tex] \int_0^1 \int_0^{2\pi} \int_0^1 1 \, dr \,d\theta \,dz [/tex]

is this correct?
 
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  • #2
Yep, that's the cylindrical coordinate version of the stated problem.
 
  • #3
and when I evaluate this I got 2*pi*r, but the answer doesn't seem to be correct...
 
  • #4
Keep in mind that after getting the antiderivative of the function you need to evaluate it at the upper and lower limits of integration and subtract each time. It looks like you did this for [itex]\theta[/itex] and z, but what about r? Since r is not a limit of integration for either [itex]\theta[/itex] or z, you're right in thinking that it shouldn't appear in the answer.

In addition, we can figure out what the answer will be without actually doing the integral if we think about it as the volume of a solid object. If you can figure out what sort of object is described by these limits of integration, then you'll be able to check your solution by comparing it to the formula for the volume of whatever shape this is.
 

1. What is a triple integral?

A triple integral is a mathematical tool used in multivariable calculus to calculate the volume of a three-dimensional region. It is essentially an extension of the double integral, which is used to calculate the area of a two-dimensional region.

2. How is a triple integral evaluated?

A triple integral is evaluated by breaking down the three-dimensional region into smaller, simpler shapes (such as rectangular prisms or cylinders) and then integrating over each of these shapes. This involves finding the limits of integration for each variable and then multiplying the integrals together.

3. What is the difference between a definite and indefinite triple integral?

A definite triple integral has specific limits of integration, meaning that it is being evaluated over a specific region. An indefinite triple integral does not have limits of integration and is typically used to find a general solution to a problem.

4. What are some real-world applications of triple integrals?

Triple integrals have various applications in physics, engineering, and economics. For example, they can be used to calculate the mass of a three-dimensional object with varying density, the center of mass of a solid object, and the volume of a fluid flowing through a three-dimensional region.

5. How can I check if my triple integral is correct?

You can check if your triple integral is correct by comparing it to the known volume of the three-dimensional region, if applicable. Additionally, you can check your work by evaluating the triple integral using different methods (such as switching the order of integration) and seeing if you get the same result.

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