Finding Limits for Triple Integrals: How to Solve for the Intersection of Planes

In summary, the conversation involves finding the volume of a region using a triple integral. The equations V=∫∫∫dV=∫∫∫dxdydz are mentioned. The individual is struggling with finding the limits to integrate with and has plotted the equations on a graphing app. They have determined that the y-limits could be from 0 to 2, but are unsure about the x and z limits. They are then given guidance to find the intersection of the two planes and the coordinates where they intersect. The individual is still unsure of the significance of this information.
  • #1
Timebomb3750
59
0

Homework Statement



Use a triple integral to find the volume of the region. Below x+2y+2z=4, above z=2x, in the first octant.

Homework Equations



V=∫∫∫dV=∫∫∫dxdydz


The Attempt at a Solution



I have no clue where to begin as to finding those darn limits to integrate with. I'm sure I can evaluate the integral just fine, but I need help finding limits.
 
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  • #2
Well, after plotting those two equations into my mac grapher app, it seems my y-limits could be from 0 to 2. But I'm unsure as to finding my x and z limits.
 
  • #3
Any assistance would be greatly appreciated. Thanks.
 
  • #4
Timebomb3750 said:
Any assistance would be greatly appreciated. Thanks.
Patience, please.

(Look at the rules for posting on this Forum, especially as regards "bumping" your thread.)
 
  • #5
Timebomb3750 said:

Homework Statement



Use a triple integral to find the volume of the region. Below x+2y+2z=4, above z=2x, in the first octant.

Homework Equations



V=∫∫∫dV=∫∫∫dxdydz

The Attempt at a Solution



I have no clue where to begin as to finding those darn limits to integrate with. I'm sure I can evaluate the integral just fine, but I need help finding limits.

Timebomb3750 said:
Well, after plotting those two equations into my mac grapher app, it seems my y-limits could be from 0 to 2. But I'm unsure as to finding my x and z limits.
Where do the planes, x+2y+2z=4, and, z=2x, intersect?

Where does each of those planes intersect the coordinate axes?
 
  • #6
SammyS said:
Where do the planes, x+2y+2z=4, and, z=2x, intersect?

Where does each of those planes intersect the coordinate axes?

Well, z=2x goes through the entire the y-axis, but doesn't intersect any other axes. x+2y+2z=4 intersects axes at x=4, y=2, and z=2.

The two planes intersect at 2y+5x=4.

But what's your point? What do I get out of this?
 
  • #7
Timebomb3750 said:
Well, z=2x goes through the entire the y-axis, but doesn't intersect any other axes. x+2y+2z=4 intersects axes at x=4, y=2, and z=2.

The two planes intersect at 2y+5x=4.

But what's your point? What do I get out of this?
I should have asked, "Where does each of those planes intersect the coordinate planes?"

The intersection of the two planes is a line. The equation, 2y+5x=4, specifies a plane !
 

Related to Finding Limits for Triple Integrals: How to Solve for the Intersection of Planes

What is a triple integral?

A triple integral is an integral that integrates a three-dimensional function over a region in three-dimensional space.

When do you use triple integrals?

Triple integrals are used when dealing with three-dimensional objects or functions, such as finding the volume of a solid or the mass of a three-dimensional object.

How do you set up a triple integral?

To set up a triple integral, you need to define the limits of integration for each variable (x, y, and z) and determine the correct order of integration based on the shape of the region being integrated over.

What are the applications of triple integrals?

Triple integrals have various applications in physics, engineering, and other fields. They are commonly used to find the mass, center of mass, and moment of inertia of a three-dimensional object, as well as to calculate the volume of a solid bounded by surfaces.

What are the challenges of using triple integrals?

Triple integrals can be challenging to set up and evaluate, as they require a good understanding of three-dimensional geometry and calculus. Additionally, the limits of integration can be difficult to determine for complex regions. Using computer software or graphing tools can help with these challenges.

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