Problem Sheet 1
                      DEN5200 Control Systems Analysis and Design


1. Find the Laplace transform of the following function:
                
                 0
                          (t < 1)
                
                  t+1      (1 ≤ t < 3)
        f (t) =
                 4
                          (3 ≤ t ≤ 4)
                
                  0        (t > 4)

2. (a) Find the Laplace transform of f (t) = 1 + 7t2 + sin 2t + e−2t cos 3t.
                                                        s+2
   (b) Find the inverse Laplace transform of F (s) = s2 +6s−7 .
                                                                          s+1
    (c) Find the inverse Laplace transform of F (s) =                  s2 −2s+5
                                                                                .
3. Find the inverse Laplace transform of the following functions:
             5                   2s+3                      10                         2(s+1)                 10
   (a)   (s+1)(s+2)     (b)   s3 +2s2 +s
                                               (c)   (s+2)(s2 +2s+5)
                                                                            (d)     s(s2 +s+2)
                                                                                                 (e)   s(s2 +4)(s+1)

4. Use Laplace transforms to solve the following ordinary differential equation
           dy
              − 2y = 3 cos t
           dt
   given y(0) = 2.
5. Use Laplace transforms to find the solution of the following differential equation
           d2 y
                + 9y = sin 2t
           dt2
   given that y(0) = 1 and y ′ (0) = 0.
6. Find the solution of the following differential equation
           d3 x    d2 x
                − 3 2 + 4x = 0
           dt3     dt
                                           2
   given that x = 1,     = −1 and d 2 = 0 at t = 0.
                        dx
                        dt         dt
                                      x

                              (         )
               At , where A =   −5 3
7. Calculate e                            .
                                −2 0
                              (             )
               At , where A =    14     10
8. Calculate e                                .
                                −20 −14


                                                      1

Den5200 ps1

  • 1.
    Problem Sheet 1 DEN5200 Control Systems Analysis and Design 1. Find the Laplace transform of the following function:   0  (t < 1)  t+1 (1 ≤ t < 3) f (t) =  4  (3 ≤ t ≤ 4)  0 (t > 4) 2. (a) Find the Laplace transform of f (t) = 1 + 7t2 + sin 2t + e−2t cos 3t. s+2 (b) Find the inverse Laplace transform of F (s) = s2 +6s−7 . s+1 (c) Find the inverse Laplace transform of F (s) = s2 −2s+5 . 3. Find the inverse Laplace transform of the following functions: 5 2s+3 10 2(s+1) 10 (a) (s+1)(s+2) (b) s3 +2s2 +s (c) (s+2)(s2 +2s+5) (d) s(s2 +s+2) (e) s(s2 +4)(s+1) 4. Use Laplace transforms to solve the following ordinary differential equation dy − 2y = 3 cos t dt given y(0) = 2. 5. Use Laplace transforms to find the solution of the following differential equation d2 y + 9y = sin 2t dt2 given that y(0) = 1 and y ′ (0) = 0. 6. Find the solution of the following differential equation d3 x d2 x − 3 2 + 4x = 0 dt3 dt 2 given that x = 1, = −1 and d 2 = 0 at t = 0. dx dt dt x ( ) At , where A = −5 3 7. Calculate e . −2 0 ( ) At , where A = 14 10 8. Calculate e . −20 −14 1