Now use L'Hopital's.
Why can't I see this I don't know...
lim( as x approaches pi/2 from the left) (secx - tanx)
can't use math tags worth a damn.
Im pretty sure this is lhospital's rule because just taking the limit gives me 1 + infinite which is not the correct answer, I converted with the natural log and did common denominator but I cant think anymore.. studying for 5 finals (calc and physics being 2) just makes my brain melt