Multivariable caclulus

1. (6 points) a) What is the angle (in radians) between the planes -1x + ly =2 and 5x + 2z = -5 in R3? b) If u . v = -4 and | |u x v| | = 9, what is the angle 0 (in ra- dians) between the vectors i and v? Your answer should be a number between 0 and It. 0 = c) If u . V = -4, |ux v| | =9, and | |u| | = 1, what is | |VI|? 2. (7 points) Let v = (-5, 1, -10). a) projs((-4, 10,-6) ) =_ b) What point on the line (-4, 10, -6) +tv is nearest to the origin (0, 0, 0)? c) The set of all points P = (x, y, z) such that proj,(OP) = (25, -5,50) forms a plane. Write an implicit equation for that plane