MATH 251 Midterm: MATH 251 PSU M251Exam 2(fa09)
Document Summary
This exam has 11 questions for a total of 100 points. In order to obtain full credit for partial credit problems, all work must be shown. Credit will not be given for answers not supported by work. You may not use a calculator on this exam. Please turn off and put away your cell phone. The last sheet of the booklet contains a table of laplace transforms and may be detached. November 2, 2009: (5 points) match the phase portraits with their names by entering the numbers in the blanks below. 4 (a) (b) (c) (d) (e) node saddle spiral center proper node: (5 points) consider the mechanical system represented by the ode: y + 4y + 5y = 0. The system is (a) underdamped (b) critically damped (c) overdamped (d) in resonance. November 2, 2009: (5 points) let f (t) = u(t 2)et 2 sin(3t 6), where u(t c) = uc(t) = (cid:26) 0.
