$6\mathrm{.}15$ Alternative formula for angular acceleration. $($Section $8\mathrm{.}3).$

Show$/$prove ${?}^N$vec$({)}^B\frac{N_d{N}_{\text{v}\text{e}\text{c}({)}^B}}{dt}$ can also be calculated as ${?}^N$vec$({)}^B=\frac{{?}^B{d}^N\text{v}\text{e}\text{c}({)}^B}{dt}.$