( 1 point) Consider the following parametric equation. $$ \begin{array}{1} x=20(\cos \theta+\theta \sin \theta) W y=20(\sin \theta-\theta \cos \theta) \end{array} $$ What is the length of the curve from $\theta=0$ to $\theta=\frac{1}{2} \pi ?$ Answer: CS.VS. 1423||