Solving Z Transform of Difference Equation: x(n+2)-0.3679x(n+1)+0.3679x(n)

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Discussion Overview

The discussion revolves around solving a difference equation using the Z-transform. The equation involves an input function defined by specific values at discrete points, and participants are attempting to determine the output function x(n) based on this input.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant presents the difference equation and attempts to apply the Z-transform, expressing confusion about how to proceed with the solution.
  • Another participant points out that the problem lacks specified initial conditions, suggesting that this makes the problem unsolvable in its current form.
  • A third participant asserts that the question provided is complete and implies that the input function is not a standard step function, indicating that the specific values of u(n) must be utilized to construct the input signal for analysis.

Areas of Agreement / Disagreement

There is disagreement regarding the completeness of the problem statement, with one participant asserting it is complete while another insists that initial conditions are necessary for a solution.

Contextual Notes

Participants express uncertainty about how to incorporate the specific values of the input function u(n) into their solution process. The discussion reflects a reliance on the definitions of the input function and the initial conditions, which remain unresolved.

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Homework Statement


consider the difference equation
x(n+2)-0.3679x(n+1)+0.3679x(n)=0.3679u(n+1)+u(n)
where u(n) is the input and given by
u(n)=0 n<0
u(0)=1
u(1)=0.2142
u(2)=-0.2142
u(n)=0 n=3,4,5...
determine the output x(n)





The Attempt at a Solution


let A=0.3679 and B=0.3642
i took z transform for both sides so it became.
z^2 x(z)-z^2x(0)-zx(1)-A[zx(z)-zx(0)]+Ax(z)=A[zu(z)-zu(0)]+Bu(z)
x(z)[z^2-Az+A]+x(0)[Az-z^2]-zx(1)=A[zu(z)-zu(0)]+Bu(z)
x(z)[z^2-Az+A]=A[zu(z)-zu(0)]+Bu(z)-x(0)[Az-z^2]+zx(1)

then what can i do?
also how can i make use of u(1)=0.2142
u(2)=-0.2142
i am too confused and need help.
 
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To solve the problem, you need to specify some initial conditions. As it stands, it's unsolvable.
 
this is the full question given to me to solve and i am sure it is complete.
 
late reply ,, have you known the correct solution ?

the key that the input is not a step function , u have to use the u(0) , u(1) ... etc to draw the input and find expression to it .
 

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