Intersections:

Find the point at which the curves intersect and then find the angle of intersection. $$\mathbf{r}_1(t) = \langle e^{3t}, 4\sin(t+\frac{\pi}{2}), t^2-1 \rangle$$ $$\mathbf{r}_2(s) = \langle s, 4, s^2-2 \rangle$$