Problems defining a polynomial in the z domain

Hello, I am trying to get a inverse Z transform of the following equation:

G(z) = (0.6321*z^-1)/((1-z^-1)*(1-0.3679*z^-1))

using the code

syms z k
F = (0.6321*z^-1)/((1-z^-1)*(1-0.3679*z^-1))
iztrans(F, z, k)

However, geting the following error:

Error: Unexpected MATLAB expression.

What is wrong?

Answer 1

[John BG]

Araujo

try the following

syms z n
F(z) = (0.6321*z^-1)/((1-z^-1)*(1-0.3679*z^-1))
f(n)=iztrans(F,z,n)

F(z) = 6321/(10000*z*(1/z - 1)*(3679/(10000*z) - 1))
f(n) = 1 - (3679/10000)^n

check that

ztrans(1 - (3679/10000)^n)
=
z/(z - 1) - z/(z - 3679/10000)

is the same as your initial function in z domain.

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thanks in advance

John

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Answer 2

[Walter Roberson]

0.3679z is not valid syntax. You need to add the multiplication symbol, 0.3679*z

[Francisco Araujo]

I edited the text. I just wrote wrong here. Still with problems... =/