If $f(x,y,z)=e^{x}yz$ and $\frac{?}{\text{b}\text{a}\text{r}}(r(t))=cos\frac{t}{b}ar()+3s\frac{{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}}{b}ar()+\frac{t^3}{b}ar(k),$ find the rate of change of $f(x,y,z)$ along $\frac{?}{\text{b}\text{a}\text{r}}(r(t))$

Consider the function $f(x,y,z)=e^{x}yz$ in Question $6.$ Answer each of the following: