1+tan2A1+cot2A =
sec2A
-1
cot2A
tan2A
1+tan2A1+cot2A =1+tan2A1+1tan2A =1+tan2Atan2A+1tan2A =(1+tan2A)(tan2A)(tan2A+1) = tan2A.
Question 5 (x) Prove the following identities, where the angles involved are acute angles for which the expressions are defined. (1+tan2A1+cot2A)=(1−tanA1−cotA)2=tan2A