# RCos(a+b) Clarification

Am i right in saying that when your comparing co-efficients for RSin(a+b) you swap over for the coefficients for sin and cos, while in RCos(a+b) you dont swap the co-efficients?

RSin(x+a)= RSinxCosa + RCosxSina
4Sin + 1Cos = RSinxCosa + RCosxSina

RSina = 1
RCosa = 4

BUT for RCos(x+a) = RSinxCosa + RCosxSina

4Sin + 1Cos = RSinxCosa + RCosxSina

RSina = 4
RCosa = 1

Do you see what i mean?

Thanks

$$sin(x+a) \neq cos(x+a)$$