If $\displaystyle \bold{r}(t) = (t^2-t, t \sqrt{2t-t^2}), 0 \leq t \leq 2 $ is $\displaystyle \bold{u}_r = \frac{(t^2-t, t \sqrt{2t-t^2})}{\sqrt{(t^2-t)^{2} + t^{2}(2t-t^2)}} $ and $\displaystyle \bold{u}_\theta = \frac{(t \sqrt{2t-t^2}, t^2-t)}{\sqrt{(t^2-t)^{2} + t^{2}(2t-t^2)}} $?