1 Answers
Best Answer
Start with the characteristic equation
r^(3)-3r^(2)+3r-1=0
Factor the constant. -1=(1*-1). First try r=1
(1)^(3)-3(1)^(2)+3(1)-1=0
True statement, so r-1=0 is a factor
Rearrange the terms so it's easier to take out the known factor.
r^(3)-r^(2)-2r^(2)+2r+r-1=0
Factor out the (r-1) term
r^(2)(r-1)-2r(r-1)+(r-1)=0
(r-1)(r^(2)-2r+1)=0
Factor the binomial
(r-1)((r-1)(r-1))=0
(r-1)(r-1)(r-1)=0
Triple root, multiply by t for each repeat
Result:
Y=c_(1)e^(t)+c_(2)te^(t)+c_(3)t^(2)e^(t)