Thread: linear algebra - concept proofs

Ok I recalculated and got
[-(4/5)*2^n+ (9/5)*.5^n (6/5)*2^n - (1/5)*.5^n
-(4/5)*3^n- (9/5)*.5^n (6/5)*3^n + (1/5)*.5^n]
for the product of the three matricies

Closer, but still no cigar. I think you're making arithmetic errors in your matrix multiplication. You've got



Now, one step at a time. Show me either or Then show me

I recalculated, is it correct this time?

I get

and



You're even closer than before. Just watch those minus signs!

So what happens next?

Can I trake the limit from here? Or do I multiply by x vector first?

It probably makes no difference; however, to play it safe, multiply by the x vector first.

Ok so if I multiply that in I should get a 2x1 matrix correct? Then I take the limit

Correct. What do you get?

Right. But you know that . That turns out to be important for computing the limit. I would eliminate one of those components. What does that give you?

umm.. I'm not sure if this is correct but would i distribute the x's and cancel out the [tex]0.4x_{1}+.01x_{2} and the same for the 0.6 one?

Well, you know that Therefore, Hence, I can represent the vector as



Multiply your times this vector, and then take the limit. What do you get here?

taking the limit, wouldn't all the ^n terms go to 0? So then I have

so the terms cancel to

Excellent! In your write-up, you might want to mention why all the exponentiated terms vanish in the limit.

So, that pretty much wraps up your first two problems. Have you gotten a good start on the third problem?

Just as a heads-up: it is considered better both to write up your original problem in LaTeX, as well as not to include more than two related problems in one thread.

I enjoyed these problems myself. Have a good one!

Thank you so much for guiding me through it, it helps so much more than just giving me an answer.

I'm trying to do the third but I can't find a relationship between eigenvectors of A and A transpose. The eigenvalues are the same but that doesn't mean it will have all the eigenvectors unless its guaranteed you get an eigenvector when you have an eigenvalue, which i'm pretty sure it's not.


Thanks for the heads-up, I'll take the time to write it up next time, it just takes a while since I'm not too familiar with the LaTeX