(10 points) Each of the following multiple choice problems has one correct answer. Circle it. You do not need to show any reasoning. (a) Suppose a 7...

I have the answers but I'm still struggling. Especially on #1.a Please help.

1. (10 points) Each of the following multiple choice problems has one correct answer. Circle it.You do not need to show any reasoning. (a) Suppose a 7é 0 and projab : a x b. Then...(i) b = a. (ii) b = —a. (iii) b = 0. (iv) b is orthogonal to a, but b 7e 0. (b) Let P be the plane through (0,0,0), (1,1,2), and (2,0,0). Then ”P also contains... (3 Let E be the line r t : 415,215, 2 +t and let P be the lane a: — 3 + 22 : 4. Then 6 is...P y(i) parallel to P (ii) orthogonal to 13. (iii) contained in ZP. (iv) none of these. (d) Suppose S is the set of points P such that the distance from P to the z—aXis is 1. ThenS is... (i) two planes. (ii) a cone. (iii) a circular paraboloid. (iv) a cylinder. (e) Let T(t) be the unit tangent vector for r(t), and suppose |r’(0)| : %. Then...(i) T(0) = 214(0). (ii) T(O) = %r’(0). (iii) T(0) = r’(0). (iv) T(0) = 0.