https://tube.cosmicflow.space/videos/watch/87fc6a90-4e13-41bc-9ed9-5bfc9c4efb81 This lecture is part of an online undergraduate course on complex analysis. We show how to express mutliplication of complex numbers using polar coordinates. As applications we show that complex numbers all have n'th roots, and derive the formulas for sin and cos of multiple angles. For the other lectures in the course see https://www.youtube.com/playlist?list=PL8yHsr3EFj537_iYA5QrvwhvMlpkJ1yGN Wed, 07 Oct 2026 15:35:44 GMT https://validator.w3.org/feed/docs/rss2.html PeerTube - https://tube.cosmicflow.space https://tube.cosmicflow.space/lazy-static/avatars/8891227d-e60f-40aa-88be-4c856c6a73dc.png https://tube.cosmicflow.space/videos/watch/87fc6a90-4e13-41bc-9ed9-5bfc9c4efb81 All rights reserved, unless otherwise specified in the terms specified at https://tube.cosmicflow.space/about and potential licenses granted by each content's rightholder.