SinA+CosB及其它的和与积转换

角的和差倍半

​​​Cos(A+B) = CosACosB - SinASinB
Cos(A-B) = CosACosB + SinASinB
Sin(A+B) = SinACosB + CosASinB 
Sin(A-B) = SinACosB - CosASinB 

Cos2A = (CosA)^2 - (SinA)^2
Sin2A = 2SinACosA

CosA + CosB = 2Cos((A+B)/2)Cos((A-B)/2)
CosA - CosB = 2Sin((A+B)/2)Sin((A-B)/2)
SinA + SinB = 2Sin((A+B)/2)Cos((A-B)/2)
SinA - SinB = 2Sin((A-B)/2)Cos((A+B)/2)

CosA + SinA = √2Cos(A-π/4)

CosA + SinB = 2Cos((A+B)/2-π/4)Sin((B-A)/2+π/4)

CosACosB = Cos((A+B)/2) + Cos((A-B)/2)
SinASinB = Cos((A+B)/2) - Cos((A-B)/2)
SinACosB = Sin((A+B)/2) + Sin((A-B)/2) ​​​​