- #1
e^(i Pi)+1=0
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- 1
Homework Statement
Solve 2x''+3x'+40x = 40y+3y'
Homework Equations
y = 0.05sin(10t)
The Attempt at a Solution
I used the annihilator method to find the answer of x(t) = Acos(10t)+Bsin(10t)+Ce-0.75tcos(sqrt(311)/4t)+De-0.75tsin(sqrt(311)/4t) where A, B, C and D are constants.
The initial conditions were given as x(0)=0, x'(0)=0, x''(0)=0 and I used 2x''(0)+3x'(0)+40x(0) = 40y(0)+3y'(0) for the last one giving:
0 = A + C
0 = 10B - 0.75C + [sqrt(311)/4]D
0 = 100A +(151/8)C + 3[sqrt(311)/8]D
-160A+30B = 1.5
I know these are right because I double checked with MATLAB so I'm not really sure what's wrong, but as I said the set is not linearly independent.