computing flux integral just given this question. compute the flux out of the unit circle, C. $$F(x,y)=\langle x+2y,3x+4y\rangle $$
i am not sure on how to solve this. Usually the flux would include Z function. please help!

The flux of $F(x,y)$ across $C$ is given by $\int_C F(x,y)\cdot n\,ds$, where $n$ is the outward normal vector to $C$. Using the planar divergence theorem, you could also calculate this integral as:
$$\int_C F(x,y)\cdot n\,ds=\iint_D\nabla\cdot F(x,y)\,dA$$
Where $D$ is enclosed by $C$ (in this case $D$ is the unit disk).
