number 9 for section 9.3

In Problems 9-12, vectors are given in their polar coordinate representation (length r, and angle & measured counterclock- wise from the positive x-axis). Find the representation of the vector [ in Cartesian coordinates. 9. r = 2, a = 60 10. r = 3, a = 120 11. r = 1,a = 180 12. r = 5, a = 270