I am trying to evaluate this integral using divergence theorem.
$$\int_{R_\infty}\nabla_R \cdot J_R R dR$$ where $R=\hat{i}x+\hat{j}y$, $R_\infty=((x,y)|-\infty<x,y<\infty)$, $\nabla_R=\hat{i}\frac{\partial}{\partial x}+\hat{j}\frac{\partial}{\partial y}$, $J_R=-D\nabla_RP+\hat{e}VP$, $\hat{e}=\hat{i}+\hat{j}$, $P$ is variable, $D, V$ are constants.
Is it wise to use integration by parts but then I need to know how to evaluate $\int_{R_\infty}\nabla_R \cdot J_R dR$ this first?