MAT244-2013S > Final Exam


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Victor Ivrii:
y^{(4)} -3y''-4y = \sin (t)+8 t.

Jason Hamilton:
solve homogeneous->  roots are i,-i,2,-2

Yh=c1 e^2t +c2 e^-2t +c3 cost +c4 sint

Yp-> undetermined coefficients-> Yp= Atcost +Btsint +Ct +D

evaulate polynomial terms => C=-2. D=0

evaulate sinusoidal terms => A=1/10 B=0

Y= c1 e^2t +c2 e^-2t +c3 cost +c4 sint + (1/10)tcost -2t

Jason Hamilton:
Also, I MIGHT have used 'x' instead of 't' on the test, would I lose marks if I used the wrong variable?

Victor Lam:
i did this

Benny Ho:


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