Comments by "test143000" (@test143000) on "The Math Sorcerer" channel.

  1. "j" is used as this is a book for electrical engineers, as "i" was a notation for an electrical current in this trade. I found this explanation in "Introduction to Laplace Transforms for Radio and Electronic Engineers" by W.D. Day, 1960.
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  2. It may be too late to make a discovery, but it is never too late to study.
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  3. I think this a photocopy version of the original book. USSR never used such binding, and some imperfections on pages look like a result of photocopying process of early 1990s.
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