Could somebody please help me with these questions:
From C3 book, ex. 7A
18) Given that 3sin(x-y)-sin(x+y)=0, show that tanx=2tany.
b) Solve 3sin(x-45)-sin(x+45)=0 for 0<=θ<=360.
19) Given that sinx(cosy+2siny)=cosx(2cosy-siny), find the value of tan(x+y).
23) Given that cosy=sin(x+y), show than tany=secx-tanx.