I know this is below most of those that peruse these forums, but I've been giving myself an ulcer trying to figure these silly things out.
The first problem starts out as
(1-sin^2(x))(1+tan^2(x))=1
and I've got it down to
(sin^2(x)/tan^2(x))-sin^2(x)=1
but from there I've got no idea...