(start out array l Rightarrow sin Acos C + sin Ccos A = twocos Asin C\ Leftrightarrow sin Acos C = cos Asin C;(*)conclude array ) (begin array l A subset B Leftrightarrow forall x in the Rightarrow x in B\A notsubset B Leftrightarrow exists x within a Rightarrow x https://onthihk55776.blogsvila.com/30344664/top-guidelines-of-on-thi-giua-hk-1-toan-10