Question

Prove: cos(x+y)/cosxsiny=coty-tanx

Answer 1

So far I got
cosxcosy-sinxsiny/cosxsiny

Answer 2

you are almost there, split the numerator into two and then simplify:\[\frac{\cos(x+y)}{\cos(x)\sin(y)}=\frac{\cos(x)\cos(y)-\sin(x)\sin(y)}{\cos(x)\sin(y)}=\frac{\cos(x)\cos(y)}{\cos(x)\sin(y)}-\frac{\sin(x)\sin(y)}{\cos(x)\sin(y)}\]

Answer 3

Thank you I got it!

Answer 4

yw :)