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Help with 2 problems!

  • Thread starter ballajr
  • Start date
  • #1
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Homework Statement



1) Find the General Solution to:
(D3 - D2 + D - I)[y] = t5 + 1

2) Prove or disprove that there are two constants A and B such that:
t2D - tD - 8I = (tD + AI)(tD + BI)



Homework Equations




The Attempt at a Solution



1) I can't figure out how to attempt this one. Doesn't make sense to me.
2) I should FOIL out the RHS of the equation, but I did that on paper and it didn't make too much sense to me.
 

Answers and Replies

  • #2
gabbagabbahey
Homework Helper
Gold Member
5,002
6
1) I can't figure out how to attempt this one. Doesn't make sense to me.
There are two methods that immediately come to mind:

(1)Use the method of Undetermined Coefficients

(2)Use the annihilator method

2) I should FOIL out the RHS of the equation, but I did that on paper and it didn't make too much sense to me.
Show us what you've got, and keep in mind that to calculate something like [itex]D(tD)[/itex] you need to use the product rule.
 
  • #3
9
0
There was a typo in #2:

2) Prove or disprove that there are two constants A and B such that:
t2D2 - tD - 8I = (tD + AI)(tD + BI)
 
  • #4
33,158
4,842
There are solutions for A and B if you permit complex solutions.
 

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