Determine the Cartesian equation of the circle given by the parametric equations

A function is defined parametrically by

If    and    are two points that lie on the graph of the function, then find the shortest distance along the graph from to .   (2 marks)

The diagram shows a semicircle.
 

Which pair of parametric equations represents the semicircle shown?

An equation can be expressed in the parametric form

1.  Express the equation in Cartesian form.  (2 marks)
   

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2.  Sketch the graph.  (1 mark)
   

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Sketch the curve described by these two parametric equations

   for   .  (3 marks)