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Triple Integrals

Extending Riemann sums and iterated integration to functions of three variables, computing volumes and masses of solid regions.

Active Calculus Multivariable, Triple Integrals

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4 exercises

Activity 12.7.2

Set up and evaluate an iterated integral that will evaluate the triple integral of f(x,y,z)=x−y+2zf(x,y,z) = x-y+2z over the box B=[−2,3]×[1,4]×[0,2]B = [-2,3] \times [1,4] \times [0,2].

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Activity 12.7.4

There are several other ways to set up the integral to give the mass of the tetrahedron in Example.

  1. How many different orders of integration could be used for iterated integrals that are equal to the integral in equation?

  2. Set up an iterated integral, integrating first with respect to zz, then xx, then yy that is equivalent to the integral in equation. Before you write down the integral, think about Fig…

2.5

Exercise 28

Consider the solid that lies between the paraboloids z=g(x,y)=x2+y2z = g(x,y) = x^2 + y^2 and z=f(x,y)=8−3x2−3y2z = f(x,y) = 8 - 3x^2 - 3y^2.

  1. By eliminating the variable zz, determine the curve of intersection between the two paraboloids, and sketch this curve in the xyxy-plane.

  2. Set up, but do not evaluate, an iterated integral expression whose value determines the mass of the solid, integrating first with respect to zz, then yy, then xx. Assume the the solid's density is given by δ(x,y,z)=1x2+y2+z2+1\delta(x,y,z) = \frac{1}{x^2 + y^2 + z^2 + 1}.

  3. S…

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Exercise 29

In each of the following problems, your task is to

  1. Sketch, by hand, the region over which you integrate

  2. set up iterated integral expressions which, when evaluated, will determine the value sought

  3. use appropriate technology to evaluate each iterated integral expression you develop

In some problems you may be able to use a double rather than a triple integral, and polar coordinates may be helpful in som…

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Adapted from Active Calculus Multivariable © 2013–2026 Nicholas Long, Mitchel T. Keller, and Steven Schlicker. Licensed under CC BY-SA 4.0. Source: Active Calculus Multivariable. Imported at revision 692c03c.