# Lecture 7 Blog, ECE438 Fall 2011, Prof. Boutin

Wednesday September 7, 2011 (Week 3) - See Course Outline.

In Lecture 7, we finished discussing the properties of the ROC for causal, anti-causal and mixed-causal signals. We also had a lengthy discussion about infinity in the complex plane, and mentioned that z-transforms may or may not converge at infinity. No, there is no homework this week. But I expect each and everyone of you to work on the practice problems.

Related Rhea pages (please feel free to comment/discuss directly on these pages):

- Some tricks to deal with the geometric series (from William Schmidt)
- Yes, the geometric series also holds for complex numbers!

## Action items

Solve the following practice problems and share your answer on the corresponding pages:

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