Question $9$: $(1$ point$)$

$a=(-8t,2t^{-2},-5t),$ and $,b=(cos(2t),0,7sin(t))$

find

$\frac{d}{dt}(a*b)=$

$\frac{d}{dt}(ab)=$

$$

$$

The syntax for entering a vector is $($:$a,b,c$:$)$