I'm stuck again... I don't know why I am having so much trouble with these. There is clearly something I'm just not seeing.

1 + cos2x = cotx sin2x

I think I need to simplify the right hand side?

This is what I've done, but I'm making a real mess of things....

cotx sin2x

= (cosx/sinx)(sin2x)

= cosx sin2x/ sinx

= [cosx (2sinx cosx)] / sinx

And then I'm lost...