# Homework Help: Greens Theorem

1. Jul 16, 2012

### gtfitzpatrick

1. The problem statement, all variables and given/known data

Calculate $\oint _c xdy-ydx$ where C is the straight line segment from$(x_1 , y_1) to (x_2 , y_2)$

2. Relevant equations

3. The attempt at a solution

so from Greens theorem I get $\oint _c xdy-ydx$ = $\int\int \frac{\partial x}{\partial x} + \frac{\partial y}{\partial y} dxdy$

=2 $\int^{x_2}_{x_1}\int^{y_2}_{y_1} dydx$
=2[$(y_2 - y_1)(x_2 - x_1)$ ]

Last edited: Jul 16, 2012
2. Jul 16, 2012

### LCKurtz

For Green's theorem you need a line integral along a curve which encloses an area. You don't have that so Green's theorem has nothing to do with this problem. Just work the line integral itself out.

3. Jul 16, 2012

### gtfitzpatrick

Hi LCkutz,
Aghhh so he threw it in as a trick question into the greens theorem section. Sneeky!
Thanks LC