Suppose the functions y1 t e2t and y2 t e2t span the solut
     Suppose the functions y_1 (t) = e^-2t and y_2 (t) = e^2t span the solution space for the homogeneous linear DE:  L(y) = 0  Specify the form of the solution to the non-homogeneous equation L(y) = e^2t 
  
  Solution
Since e^{2t} is already a solution to homogeneous ode so the guess for particular solution is
yp=Cte^{2t}
HEnce form of general solutoin is
y=Ae^{-2t}+Be^{2t}+Cte^{2t}

