Posted by Hannah on .
Perform the addition or subtraction.
tanx  sec^2x/tanx
tan^2(x)/tan(x)  sec^2x/tanx =
tan^2x sec^2x / tanx
then I use the identity 1+tan^2u=sec^2u
I do not know what to do at this point.

PreCal 
Reiny,
from you second line
tan^2(x)/tan(x)  sec^2x/tanx
= (tan^2 x  sec^2 x)/tanx
= (tan^2 x  (1 + tan^2 x))/tanx
= 1/tanx or cotx or sinx/cosx