Divergence theorem with inequality

In summary: Bottom: ##\vec R(x,y) = \langle x,y,0\rangle,~0\le x^2+y^2\le 4##Top: ##\vec R(x,y) = \langle x,y,3\rangle,~0\le x^2+y^2\le 4##Side: ##\vec R(\theta,z) = \langle 2\cos\theta,2\sin\theta,z\rangle,~0\le \theta\le 2\pi,~0\le z\le3##I have no idea what you mean by the "
  • #1
kelvin56484984
29
0

Homework Statement



F(x,y,z)=4x i - 2y^2 j +z^2 k

S is the cylinder x^2+y^2<=4, The plane 0<=z<=6-x-y

Find the flux of F

Homework Equations



The Attempt at a Solution



What is the difference after if I change the equation to inequality?

For example :
x^2+y^2<=4, z=0

x^2+y^2<=4 , z=6-x-y

x^2+y^2=4, z=6-x-y

thanks!
 
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  • #2
kelvin56484984 said:

Homework Statement



F(x,y,z)=4x i - 2y^2 j +z^2 k

S is the cylinder x^2+y^2=4, 0<=z<=3

Homework Equations



The Attempt at a Solution


[/B]
I find that the answer is 84 pi

What is the difference after if I change the equation to inequality?

For example :
x^2+y^2<=4, z=3

x^2+y^2<=4 , z=0

X^2+y^2=4, z=3

thanks!

Make a sketch and everything will become clear.
 
  • #3
kelvin56484984 said:

Homework Statement



F(x,y,z)=4x i - 2y^2 j +z^2 k

S is the cylinder x^2+y^2=4, 0<=z<=3

Homework Equations



The Attempt at a Solution


[/B]
I find that the answer is 84 pi

Answer to what??

What is the difference after if I change the equation to inequality?

For example :
x^2+y^2<=4, z=3

x^2+y^2<=4 , z=0

X^2+y^2=4, z=3

thanks!

One inequality gives the surface of the cylinder and the other gives the solid cylinder.
 
  • #4
Sorry, I made some mistake previously and I modified the question.
If I want to find the flux of the bottom face, top face, side surface of cylinder and the tangent surface of the cylinder,
How can I express it in inequality?
 
  • #5
kelvin56484984 said:
Sorry, I made some mistake previously and I modified the question.
If I want to find the flux of the bottom face, top face, side surface of cylinder and the tangent surface of the cylinder,
How can I express it in inequality?
Bottom: ##\vec R(x,y) = \langle x,y,0\rangle,~0\le x^2+y^2\le 4##
Top: ##\vec R(x,y) = \langle x,y,3\rangle,~0\le x^2+y^2\le 4##
Side: ##\vec R(\theta,z) = \langle 2\cos\theta,2\sin\theta,z\rangle,~0\le \theta\le 2\pi,~0\le z\le3##
I have no idea what you mean by the "tangent surface".
You could, and likely should, use polar coordinates for the first two instead of ##x## and ##y## parameters.
 

Related to Divergence theorem with inequality

What is the Divergence Theorem with Inequality?

The Divergence Theorem with Inequality is a mathematical theorem that relates the flux of a vector field through a closed surface to the triple integral of the divergence of the same vector field over the enclosed volume. It is a generalization of the Divergence Theorem, which only applies to equalities.

How is the Divergence Theorem with Inequality used in physics?

The Divergence Theorem with Inequality is used in physics to relate the flow of a vector field through a closed surface to the sources and sinks of that vector field within the enclosed volume. This is useful in understanding fluid flow, electric and magnetic fields, and other physical phenomena.

What is the difference between the Divergence Theorem and the Divergence Theorem with Inequality?

The Divergence Theorem only applies to equalities, while the Divergence Theorem with Inequality allows for inequalities. This means that the Divergence Theorem with Inequality is a more general theorem that can be applied to a wider range of situations.

How is the Divergence Theorem with Inequality derived?

The Divergence Theorem with Inequality is derived from the Divergence Theorem using mathematical techniques such as Stoke's Theorem and the Cauchy-Schwarz inequality. The proof involves breaking the surface into smaller pieces and applying the Divergence Theorem to each piece, then taking the sum of these pieces and applying the Cauchy-Schwarz inequality to obtain the inequality.

What are some real-world applications of the Divergence Theorem with Inequality?

The Divergence Theorem with Inequality has many practical applications, such as in fluid mechanics, electromagnetism, and even computer graphics. It is used to calculate flow rates, analyze electric and magnetic fields, and simulate fluid behavior, among other things. This theorem has also been applied in economics, biology, and other fields to model and analyze various systems.

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