## allenh98 3 years ago I need help with a complex number zeros/poles difference equations kinda thing http://i42.tinypic.com/3585rtx.png

1. 142343

www.mathway.com

2. 142343

and i be back

3. EarthCitizen

is z given ?

4. allenh98

5. allenh98

z is a variable

6. allenh98

I expanded the top, not even close to getting 0.1765 z ^ -1

7. EarthCitizen

you can use De Moivre's theorem $z ^{-n} = r ^{-n}[\cos(n \theta)-jsin(n \theta)]$

8. allenh98

that gives me 1

9. EarthCitizen

can you use MATLAB ?

10. allenh98

nvm i found the answer! just needed to fully expand it and it works itself out thx for help!!!