When are Line/Surface Integrals Used?

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In summary, the Fundamental Theorem of Line Integrals is used for curved lines, while Greens Theorem is only used for simple enclosed curves. Stokes' Theorem and Divergence Theorem are used for 3-dimensional shapes, with the latter allowing you to write a surface integral as a volume integral. Green's Theorem allows you to write a line integral around a closed curve as a surface integral over the contained surface, as long as it lies in the plane. The Fundamental Theorem of Line Integrals is used when the vector field being integrated is conservative, and it allows you to find the original function and evaluate the line integral between any two points in the field.
  • #1
Jacob87411
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I just want to verify how/what each of these is used for:

Fundamental Theorem for Line Integrals - This is like the regular fundamental theorem but you use the gradient of F? And this is used for curved lines

Greens Theorem - This is only used for simple enclosed curves

Stokes' Theorem & Divergence Theorem - I'm confused when you use these, are they for 3-dimensional shapes? Thanks
 
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Jacob87411 said:
Greens Theorem - This is only used for simple enclosed curves

Stokes' Theorem & Divergence Theorem - I'm confused when you use these, are they for 3-dimensional shapes? Thanks

The Divergence Theorem let's you write a surface integral as a volume integral.

Green's theorem let's you write a line integral around a closed curve as a surface integral over the contained surface (as long as it lies in the plane).

Not sure about the fundamental theorem of line integrals...
 
  • #3
The Fundamental Line Theorem is used when the vector field you are integrating the curve over is conservative (curl = 0). A conservative vector field is the gradient of some function so this theorem allows you to just find the original function and take the difference between any two points in the field to give the evaluation for the line integral of a curve between them.
 

FAQ: When are Line/Surface Integrals Used?

What is a line/surface integral?

A line/surface integral is a type of mathematical calculation used to find the total value of a function over a specific curve or surface. It combines the concepts of integration and vector calculus to calculate the area, volume, or other properties of a given curve or surface.

What is the difference between a line integral and a surface integral?

A line integral is used to find the total value of a function over a curve, while a surface integral is used to find the total value of a function over a surface. Line integrals are one-dimensional, while surface integrals are two-dimensional.

What is the significance of line/surface integrals in physics?

Line/surface integrals are used in physics to calculate physical quantities such as work, flux, and electric field strength. These calculations are essential in understanding and describing the behavior of physical systems.

How do you calculate a line/surface integral?

To calculate a line integral, you first need to parameterize the curve and then integrate the function along the curve using the limits of integration. For a surface integral, you need to first determine the orientation of the surface and then integrate the function over the surface using a double integral.

What are some real-world applications of line/surface integrals?

Line/surface integrals have various applications in fields such as engineering, physics, and economics. Some examples include calculating the work done by a force on an object, finding the electric field due to a charged surface, and determining the mass of an object with a varying density.

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