FirstOrDefault is an extension method used in Linq. It is often used incorrectly, leading to exceptions or ignored data. Learn techniques for accessing members of a Linq expression without the possibility of errors. "Theorem" and "theory" sound similar, but they mean completely different things. Learn the difference, and how a theorem can be part of a theory. Continuing with Claude E. Shannon's "The Mathematical Theory of Communication", we learn how to model random noise within a channel. How does this noise effect the bandwidth of the channel? How can we achieve any desired confidence in the message received, shy of certainty? The math tells us how.