12. L^{-1}left{frac{s-1}{s^2+2s+5}
ight}(t) is equal to
A. e^tleft(cos(4t)-frac{1}{2}sin(4t)
ight) B. e^{-t}left(cos(4t)-frac{1}{2}sin(4t)
ight)
C. e^{-t}left(cos(2t)-2sin(2t)
ight) D. e^tleft(cos(2t)-sin(2t)
ight)
E. e^{-t}left(cos(2t)-sin(2t)
ight)
13. L^{-1}left{frac{se^{-2s}}{s^2+pi^2}
ight}(t) is equal to
A. frac{1}{pi}u_2(t)sin(pi t) B. u_2(t)cos(pi t)
C. u_{pi}(t)cos(2t) D. frac{1}{pi}u_2(t)cos(pi t)
E. none of the above
14. Given that the matrix A = egin{bmatrix} 2 & 3 \ -3 & 2 end{bmatrix} has a complex eigenvalue 2+3i, and a
corresponding eigenvector egin{bmatrix} 1 \ i end{bmatrix}, the initial value problem
vec{Y}'=Avec{Y}, vec{Y}(0)=egin{bmatrix} 1 \ 2 end{bmatrix}
has solution
A. egin{bmatrix} e^{2t}(cos(3t)-2sin(3t)) \ e^{2t}(2cos(3t)-sin(3t)) end{bmatrix} B. egin{bmatrix} e^t(cos(3t)-2sin(3t)) \ e^t(2cos(3t)+sin(3t)) end{bmatrix}
C. egin{bmatrix} e^t(cos(3t)+sin(3t)) \ e^t(2cos(3t)-2sin(3t)) end{bmatrix} D. egin{bmatrix} e^{2t}(cos(3t)+2sin(3t)) \ e^{2t}(2cos(3t)-sin(3t)) end{bmatrix}
E. egin{bmatrix} e^{-t}(cos(3t)-sin(3t)) \ e^{-t}(2cos(3t)-2sin(3t)) end{bmatrix}