两角和与差的正余弦及倍角公式【基础知识】1、两角和与差的三角函数公式:____________________;________________________________________;________________________________________;____________________2、倍角公式:________________________________________=____________________=________________________________________ 【典型例题】例1:化简求值(无条件求件)1.的值为_________________2. __________3. 的值是 .4. .等于________________5. 的值为_____________6. =_..