93,233 views
My Telegram channel: https://t.me/berdov_math Sign up for classes: https://www.berdov.com/repetitor/ In this lesson, we will once again go over all the key methods for solving quadratic equations - from the simplest to more complex ones, requiring knowledge of the formulas for the sine and cosine of a double angle. Original video: http://www.berdov.com/docs/trigonomet...