Search results
Results from the WOW.Com Content Network
A line integral (sometimes called a path integral) is an integral where the function to be integrated is evaluated along a curve. [42] Various different line integrals are in use. In the case of a closed curve it is also called a contour integral. The function to be integrated may be a scalar field or a vector field.
Line integrals of scalar fields over a curve do not depend on the chosen parametrization r of . [ 2 ] Geometrically, when the scalar field f is defined over a plane ( n = 2) , its graph is a surface z = f ( x , y ) in space, and the line integral gives the (signed) cross-sectional area bounded by the curve C {\displaystyle {\mathcal {C}}} and ...
The integral symbol is U+222B ∫ INTEGRAL in Unicode [5] and \int in LaTeX.In HTML, it is written as ∫ (hexadecimal), ∫ and ∫ (named entity).. The original IBM PC code page 437 character set included a couple of characters ⌠ and ⌡ (codes 244 and 245 respectively) to build the integral symbol.
[48]: 163–165 F is an indefinite integral of f when f is a derivative of F. (This use of lower- and upper-case letters for a function and its indefinite integral is common in calculus.) The definite integral inputs a function and outputs a number, which gives the algebraic sum of areas between the graph of the input and the x-axis.
Just as the definite integral of a positive function of one variable represents the area of the region between the graph of the function and the x-axis, the double integral of a positive function of two variables represents the volume of the region between the surface defined by the function (on the three-dimensional Cartesian plane where z = f(x, y)) and the plane which contains its domain. [1]
The integral can be reduced to a single integration by reversing the order of integration as shown in the right panel of the figure. To accomplish this interchange of variables, the strip of width dy is first integrated from the line x = y to the limit x = z , and then the result is integrated from y = a to y = z , resulting in:
To compute integrals in multiple dimensions, one approach is to phrase the multiple integral as repeated one-dimensional integrals by applying Fubini's theorem (the tensor product rule). This approach requires the function evaluations to grow exponentially as the number of dimensions increases.
Functional integrals where the space of integration consists of paths (ν = 1) can be defined in many different ways. The definitions fall in two different classes: the constructions derived from Wiener's theory yield an integral based on a measure, whereas the constructions following Feynman's path integral do not. Even within these two broad ...