`(sec A sec B+tan A tan B)^2 - (sec A tan B + tan A sec B)^2 = 1`

(sec x sec y + tan x tan y) ^ (2) - (sec x tan y + tan x sec y) ^ (2) = 1 Prove it

1/(sec A + tan A) = sec A - tan A

IF ( sec A - tan A) ( sec B - tan B) ( sec C- tan C ) =(sec A + tan A ) ( sec B + tan B ) ( secC + tan C ) then each is equal to

(sec A + tan A -1) (sec A - tan A+1)=

If (sec A + tan A)(sec B + tan B)(sec C + tan C) = (sec A- tan A)(sec B- tan B)(sec C tan C) Prove that each side is equal to +-1.

If k=( sec A + tan A) ( sec B+ tan B) sec C + tan C)=(sec A - tan A)(sec B- tan B)(sec C - tan C) " then " k=

If (tan A + sec A) (tan B + sec B) (tan C + sec C) = (tan A -sec A) (tan B -secB) (sec C-tan C),show that each side is equal to +-1

Prove the following identities : (sec A - tan A)/ (sec A + tan A) = 1 - 2 sec A tan A + 2 tan^(2) A