二、证明恒等式和因式分解在代数式或三角式的恒等变形中经常用到换元法,下面先看一些例题:,劣.夕.2·石万十万十万=1,a bc-+几丁+-劣少之:巳知条件中的含与备=0,求证:杀+于+萦=1号与含互为到数,例证故作代换普=。,会=。,于一w后,容易看出已知条件与要求证的等式之间的关系·这时已知条 Second, to prove the identity and factorization in the algebraic or triangular constant transformation often used to change the law, the following first look at some examples:, bad. Xi. 2. Shi Wan Shiwanwanwan = 1, a bc- + Chitin + - inferior less: In the condition of knowledge and containment = 0, verification: Kill + + 萦 号 号 与 与 与 与 与 与 与 与 与 , , , , , , , , , ,. , will =. , After a w, it is easy to see the relationship between the known conditions and the required proofs.