- #1
oneamp
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Homework Statement
Find the general solution:
y'' - y' - 2y = -2t + 4t^2
Homework Equations
The Attempt at a Solution
r_1 = 2, r_2 = (-1)
Set Y(t) = At^2 + B^t + C
Y' = 2At + B
Y'' = 2A
2A - 2At + B - 2At^2 + Bt + C = -2t + 4t^2
-2At^2 + (B-2A)t + 2A + B + C = -2t + 4t^2
-2A = 4
B - 2A = (-2)
2A + B + C = 0
The solution should have -2 = A, 3 = B, and -7/2 = C.
But when I solve it, given the equations above, I don't get that. I only have A right.
What's wrong?
Thank you