## Path Integrals in the Plane, Double Integrals, and Greens Theorem in Maxima

In an earlier post I described the Maxima package MATH214 for use in my multivariable calculus class.  I’ve posted examples with applications to Gauss’s  Theorem and Stokes Theorem.

Here we take the double integration routine integrate2() and the 2D path integral integratePathv2() for a spin with a Green’s Theorem example from Stewart’s Calculus Concepts and Contexts:

And of course polar coordinates are nice too:

The two functions used above are included in the MATH214 package, but I list them below as well.

```integratePathv2(H,r,t,a,b):=block(
[H2],
H2:psubst([x=r[1],y=r[2]],H),
integrate( trigsimp(H2.diff(r,t)),t,a,b)
);

integrate2(F,xx,aa,bb,yy,cc,dd):=block(
integrate(integrate(F,xx,aa,bb),yy,cc,dd));```