1. Solve the following differential equations:
A. D (D + 3)3 (D2 +9)(D2-2x-8)y = 0
B. ym -4yn-9y'+36y =0
C. ym -4y' = x + 3 cos x + e-2x [Hint: Use undetermined coefficients]
D. yn +4y' +4y = x-2e-2x with x > 0 [Hint: Use variation of parameters]
2. Determine an annihilator for x2 e3x + 5 cos 2x.
3. Convert the following system to a first-order system:
d2x/dt2 -3dy/dt+x = sint, d2y/dt2 -tdx/dt-e'y=t2
4. Solve the following linear system of differential equations:
x1' = x1 + 2x2
x2' = 4x1+ 3x2
5. Solve the following nonhomogeneous linear system of differential equations:
x1' = x1 + 2x2 +12e3t
x2'= 4x1 + 3x2 +18e2t
6. Compute the Laplace transforms of the following functions:
A. e5t sin 3t
B. u2 (t)sin (5 (t - 2))
7. Compute the inverse Laplace transforms of the following functions:
A. 7e-2s /s2 +4
B. 3s+2/ (s -1)(s -2)
8. Solve the following initial-value problem by using Laplace transforms:
yn -4y =12e2t with y(0)=2 and y' (0) = 3.