Surface Integral between planes

In summary, the problem involves evaluating the double integral of x times the square root of the partial derivative of the surface area integral formula, over the portion of the surface defined by the given planes. The limits of integration can be found by analyzing the intersection of the plane with the x-y plane.
  • #1
hooshies
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Homework Statement



∫∫s x √(y2 + 4) where S: y2 + 4z = 16, and portion cut by planes x=0, x=1, z=0.

Homework Equations



I attempted to solve using the surface area integral formula, whereby this double integral is transformed to ∫∫f(x,y,g(x,y)) √((∂z/∂x)2 + (∂z/∂y)2 + 1) dA

The Attempt at a Solution



Solving for z in the S region, and finding partials with respect to x and y yields A(S) of √(1+(1/4)y2) which can be rewritten as 1/2 √(4+y2)

Multiplying this by the original function, which is a function of just x and y, gives ∫∫ x/2*(4 + y2) dA.

I'm having trouble finding the limits of integration for the given planes.
 

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  • #2
The limits of integration are over the foot-print in the x-y plane of the surface you're integrating over right? You drew it? It's that paraboloid-cylinder cut at the planes of x=0 and x=1 above the x-y plane and you can figure where it cuts through the x-y plane by the equation z=4-1/4 y^2. It's just a square 1x4.
 

FAQ: Surface Integral between planes

What is a surface integral between planes?

A surface integral between planes is a mathematical tool used to calculate the flux of a vector field through a surface that lies between two planes. It involves finding the double integral of a function over the surface, and is often used in physics and engineering to solve problems involving fluid flow or electric fields.

How do you calculate a surface integral between planes?

To calculate a surface integral between planes, you first need to determine the limits of integration, which are the equations of the planes defining the boundaries of the surface. Then, you need to find the unit normal vector to the surface and the vector function that represents the vector field. Finally, you can set up and evaluate the double integral using these values.

What is the significance of a surface integral between planes?

A surface integral between planes is significant because it allows us to calculate the amount of fluid or electric flux passing through a given surface. This can help us understand the behavior of fluids and electric fields in different scenarios, and can be used to solve real-world problems in various fields such as engineering and physics.

Can a surface integral between planes have negative values?

Yes, a surface integral between planes can have negative values. This occurs when the vector field is pointing in the opposite direction to the normal vector of the surface, resulting in a negative flux. It is important to pay attention to the direction of the vector field when evaluating a surface integral between planes.

What are the applications of surface integrals between planes?

Surface integrals between planes have many applications in physics and engineering. They can be used to calculate fluid flow through a surface, electric flux through a closed surface, and surface area of a curved object. They are also used in the derivation of important theorems such as the Divergence Theorem and the Stokes' Theorem.

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