trig
posted by Anonymous .
Simplify: cos x cos x
 + 
sec x1 sec x+1

is that
cosx/(secx  1) + cosx/(secx + 1) ???
of so, then using a common denominator , ...
(cosx(secx + 1) + cosx(secx  1)) / (sec^2 x  1)
= cosx(2secx)/tan^2x
= cosx(2/cosx) ( cos^2x/sin^2x
= 2cot^2 x