# Line Integral over Vector Field?

Not exactly a homework problem, a problem from a sample test. I'm boning up for my qualifying exam.

## Homework Statement

Consider the vector field:

F = (ax + by)i + (cx + dy)j

where a, b, c, d are constants.

Let C be the circle of radius r centered at the origin and going around the origin one turn in the mathematically positive direction starting from the positive x-axis.

A parameterization for C is x = r cost y = r sint, (z=0), Where 0$$\leq$$ t $$\leq$$ 2 $$\pi$$

Find the integral $$\int_{C}$$F.dR for any values of a, b, c, d (the answer may depend on a, b, c, d)

## The Attempt at a Solution

The rust is killing me. I remember that I need line integrals to solve the problem, but the setup isn't coming out of the fog.