Line Integral of Vector Function
You can consider the integral of a vector function F along a curve C. The vector function F has the components and . The path of the parameterized function is .
The parameter t reaches from a to b.
If you use this vector function then the differential d naturally is dr.
This formular expresses that there is a tangent component t of F along the path.
The trajectory of a particle r’ along a curve (the path C) inside a vector field (Source: Lucas V. Barbosa)
Now the distance gets the name ds.
The line integral over a scalar field f is the area under the curve C along a surface z = f(x,y) which is described by the field (Source: Lucas V. Barbosa)
The line integral is also equivalent to:
Example
Evaluate the line integral for the function for . The path shall be a straigt line .
First, write down a parametric function for the path.
t is from 0 to 1.
The new parameters are:
The derivative of x is
The derivative of y is
Put in these parameters into the function F for each dimension x and y.
First dimension x:
The term is filled in with and the term is filled in with
Second dimension y:
The term is filled in with
Put in the parameterized variables in an integral.