There are three questions to answer.

19. For v = -31 +6j , find unit vector u in the direction of v. (1 point) Ou=-itj Ou=- 2 O 1=- V5., 2V5 5 -it 5 O 1 =- V/3 it 2V3 3 3 20. Which of the following is a point on the plane curve defined by the parametric equations? (1 point) x = 4t y =12 +4f -1 O (4, 7 ) . (4, 207) O (-2,4 ) O (-2, 0 ) 21. Write the following parametric equations as a polar equation. (1 point) x = 2t Or= 4 cot @ csco Or= 4 tan @ sec e Or=2 cot @ csco Or= 2 tan 0 sec 9