3-(2)

$\mathbf{a}$ の回転

$$\mbox{rot} \mathbf{a} = \left( \frac{ (zx) }{\partial y} - \frac{\partial yz}{\partial z}\right) \mathbf{i}$$ (36)

$$+ \left( \frac{\partial (xy)}{\partial z} - \frac{\partial (zx)}{\partial x}\right) \mathbf{j}$$ (37)

$$+ \left( \frac{\partial (yz)}{\partial x} - \frac{\partial (xy)}{\partial y} \right) \mathbf{k}$$ (38)

$$= - y - z - x$$ (39)

$$= -x-y -z$$ (40)