.积化和差记忆口诀:积化和差得和差,余弦在后要相加;异名函数取正弦,正弦相乘取负号。和差化积记忆口诀:正加正,正在前;正减正,余在前;余加余,余并肩;余减余,负正弦。1下列等式错误的是()Asin(AB)sin(AB)2sinAcosB Bsin(AB)sin(AB)2cosAsinBCcos(AB)cos(AB)2cosAcosB Dcos(AB)cos(AB)2sinAcosB2sin15sin75()A.B. C. D13sin105sin15等于()A. B. C. D.4sin37.5cos7.5_.5.sin70cos20sin10sin50的值为()A. B.