ORDINARY DIFFERENTIAL EQUATIONS                                                                     January 2014
TEST 1
                                              (10 % coursework)
                       Instructions: Answer ALL questions. Time allocation: 1H30.
   1. Find a particular solution for the following initial-value problem that satisfy the prescribed initial
      conditions
                                   d2y
                                x 2 2  x  10 y  0 ; y1  2 , y1  5
                                             dy
                                    dx       dx
       if the general solution to the differential equation is yx  c1x cos3ln x   c2 x sin3ln x .
                                                                                                            [5 marks]
   2. Solve the following first order differential equation
                                                  xydx  3e x dy  0 .
                                                                                                            [5 marks]
   3. Solve the following first order differential equation
                                         x  3 dz  z  2 ln x ; z1  15 .
                                                  dx
                                                                                                            [5 marks]
   4. Find the values of the constants a, b and c (if any) if the differential equation given is Exact.
                                                                          dy
                                            2 x a y b  4 x3  cx 2 y 3      0
                                                                          dx
                                                                                                            [5 marks]
   5. Solve (2 y 2  2 y  4 x 2 )dx  (2 xy  x)dy  0 by finding an appropriate integrating factor
                                                                                                   [10 marks]
   6. Solve xy  2 y  xy 3
                                                                                                        [10 marks]