Suppose that $\vec{F}(x, y, z)=F_{1}(x, y, z) Wec{i}+F_2}(x, y, z) Wec{j}+F_{3}(x, y, z) ivec[k]$ is a two times continuously differentiable vector field. Verify that $$ operatorname[div}(\operatorname{curl} \ec{F}}= abla \cdot( abla \times (vec{F})=0 SP.SD.4161 $$