EL ENG 20 Midterm: ee20N-fa2012-mt1-Ayazifar-soln
Document Summary
Eecs 20n: structure and interpretation of signals and systems. 1. 1a prove ez is nonzero z c. Slick solution note eze z = 1 = ez 6= 0. While this solution is very easy to understand, it"s not obvious. We know from high school calculus that for all real a, ea > 0. From 1. b, we know |eib| = 1 and thus eib 6= 0. We initially did not give credit for this because we decided one needed to prove, ea > 0 because the proof is non-trivial, but later decided it was ne. We took o points and you may submit them for regrade. Less common solution note that for any log function, log(0) is unde ned (if you said it was , we still gave you points even though this is incorrect). Also note that there is a log function s. t. log(ez) = z. Therefore it is de ned at log(ez) and thus ez cannot be 0.
