In Exercises a parametrization is given for a curve.
(a) Graph the curve. What are the initial and terminal points, if any? Indicate the direction in which the curve is traced.
(b) Find a Cartesian equation for a curve that contains the parametrized curve. What portion of the graph of the Cartesian equation is traced by the parametrized curve?

 x = cos (π - t), y = sin (π- t), 0 ≤ t ≤ π