1717 la n[ J 8. Use the sum identity for tangent to nd the exact value of 12 . No credit will be awarded for decimal approximations. (6 points) 9. Consider the vector V = ("5.13). Part I: Find the angle (in degrees) between V = ('5.131and the xaxis, which can be approximated as the vector (1,0). (4 points) Part II: Writev in the form [I VI 003% VI sine]. Express the angle gin degrees. (4 points) Part III: Use the dot product of the vectors V = ['5-13)and W = ("42"3'1lto determine if they are orthogonal. (2 points) 10. Find the fourth roots ofthe complex number 21 = 1+ HE ' 'II. Part I: Write 21 in polar form. (2 points) Part II: Apply De Moivre's theorem to nd the modulus and angles of the roots of Z1. (6 points) Part III: What are the fourth roots of 21 = 1"" J5 \"I? (4 points)