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[SOLVED] Recurrence Relation
Solve the recurrence relation
[tex]a_{n+2}+3a_{n+1}+2a_n=3[/tex]
add the homogeneous solution to the particular solution
Characteristic: [itex]s^2+3s+2=0 \Rightarrow x=-2,-1[/itex]
Homogeneous: [itex]a_n=A(-2)^n+Bn(-1)^n[/itex]
(*here is where I'm not sure if I've gone wrong. Should it be
[itex]a_n=A(-1)^n+Bn(-2)^n[/itex] instead? How would I know?*)
anyway, not sure I've right up to here but onwards->
Particular: [itex]a_n=C3^n[/itex]
then [tex]C3^{n+2}+3C3^{n+1}+2C3^n=3^n[/tex]
letting n=0 yeilds[tex]a_n=\frac{3^n}{20}[/tex] for the particular solution
then the solution is [tex]a_n=A(-2)^n+Bn(-1)^n+\frac{3^n}{20}[/tex]
solving for A and B I got A=-1/20 and B=-3/4 and putting it all together seemed to give me nonsense.
Anyway, as you can probably see I'm not really understanding what's happening here. I would really appreciate nudge in the right direction.
Thank you kindly for you time
-kentt
Homework Statement
Solve the recurrence relation
[tex]a_{n+2}+3a_{n+1}+2a_n=3[/tex]
Homework Equations
add the homogeneous solution to the particular solution
The Attempt at a Solution
Characteristic: [itex]s^2+3s+2=0 \Rightarrow x=-2,-1[/itex]
Homogeneous: [itex]a_n=A(-2)^n+Bn(-1)^n[/itex]
(*here is where I'm not sure if I've gone wrong. Should it be
[itex]a_n=A(-1)^n+Bn(-2)^n[/itex] instead? How would I know?*)
anyway, not sure I've right up to here but onwards->
Particular: [itex]a_n=C3^n[/itex]
then [tex]C3^{n+2}+3C3^{n+1}+2C3^n=3^n[/tex]
letting n=0 yeilds[tex]a_n=\frac{3^n}{20}[/tex] for the particular solution
then the solution is [tex]a_n=A(-2)^n+Bn(-1)^n+\frac{3^n}{20}[/tex]
solving for A and B I got A=-1/20 and B=-3/4 and putting it all together seemed to give me nonsense.
Anyway, as you can probably see I'm not really understanding what's happening here. I would really appreciate nudge in the right direction.
Thank you kindly for you time
-kentt