MATH 21A Midterm: Math 21 a Midterm I 1 Fall 2009
Document Summary
Answers which are illeg- ible for the grader cannot be given credit: show your work. Except for problems 1-2, we need to see details of your computation: no notes, books, calculators, computers, or other electronic aids can be allowed, you have 90 minutes time to complete your work. Mark for each of the 20 questions the correct letter. The surface x2 + y2 + z2 + 2z = 0 is a sphere. The length of the vector h1, 2, 2i is an integer. The vector h3, 4i appears as a velocity vector of the curve ~r(t) = hcos(5t), sin(5t)i. namely, there is a t such that ~r (t) = h3, 4i. If ~t is the unit tangent vector, ~n is the unit normal vector, and ~b is the binormal vector, then ~b ~n = ~t . The curvature of a larger circle r = 2 is greater than the curvature of a smaller circle r = 1/2.
