9.If the vectors $\vec{v}(t) = 4t\vec{i} + 5t^3\vec{k}$ and $\vec{w}(t) = t^2\vec{i} - 5t\vec{j} + 2t^3\vec{k}$. Find

$$\frac{d}{dt}(\vec{w} \cdot \vec{v}) \quad (10\%)$$

and

$$\frac{d}{dt}(\vec{v} \times \vec{w}) \quad (10\%)$$