Expand tan(x+2y) (1 Viewer)

[Thylacine]

Expand tan(x+2y)

I get this far (tanx+2tanx/(1-〖tan〗^2 x))/(1-tanx 2tany/(1-〖tan〗^2 y))

but then I can't get to the answer in BOB.

Please help!

 

[rumbleroar]

Confused...where did your "y" go on the numerator?

 

[Thylacine]

rumblroar your brilliant, I substituted the wrong values.
I've just put the "y's" in the right place and it fell into place.
A bit of dancing round the room a few whoops.
Thanks

 

[Joshmosh2]

Hold on a second, I'm confused with this. Subbing the values into the equation doesn't work? Did you use double angle formula for 2y? What did you do wrong exactly 0.0