Evaluate the integral $\iint \operatorname{curl}(yi+2j)\cdot n \, d\sigma $ where $\sigma$ is the surface in the first octant made up of part of the plane $2x+3y+4z=12$ and triangular in the $(x,z)$ and $(y,z)$ planes,
MY ATTEMPT: we use stokes theorem $$\iint \operatorname{curl}(yi+2j)\cdot n \, d\sigma = \int_c F\cdot dr$$
$$\Longrightarrow \int_c F\cdot dr =\int_c (yj+ 2i)\cdot(i\,dx+j\,dy+k\,dz) $$ how we processed next