All right. "Sister Ren Dabai talks about high school mathematics" is an educational video explaining high school mathematics knowledge. It is taught by Professor Wang of Peking University Institute of Mathematical Sciences and doctoral supervisor, commonly known as "Sister Ren Dabai". This series of videos is comprehensive, easy to understand and easy to understand. It is a good self-study material for senior high school mathematics learners, and also a good helper for teachers to prepare lessons and parents' guidance.