\magnification=\magstep2


$$
\vec{A} =  A_x \hat{\imath} + A_y \hat{\jmath} + A_z \hat{k} 
$$

$$
\vec{B} =  B_x \hat{\imath} + B_y \hat{\jmath} + B_z \hat{k} 
$$

$$\eqalign{
\vec{A} \times \vec{B} \quad = \quad &(A_y B_z - A_z B_y) 
                                  \thinspace \hat{\imath} \quad + \cr
                         \quad &(A_z B_x - A_x B_z) 
                                  \thinspace \hat{\jmath} \quad + \cr
                         \quad &(A_x B_y - A_y B_x) 
                                  \thinspace \hat{k} \cr
}
$$


$$
\vec{A} \times \vec{B} \quad = \quad \left| 
               \matrix{ \hat{\imath} &\hat{\jmath} &\hat{k} \cr
                         A_x         & A_y         & A_z    \cr
                         B_x         & B_y         & B_z    \cr} \right| 
$$



$$
\vec{\tau} \quad  = \quad \vec{r} \times \vec{F} 
$$




\bye

