Mathematics
(cot A - cot B)2 + (1 + cot A cot B)2 is equal to :
sec2 A - cos2 A
sec2 A - cosec2 A
(1 + tan A)2 - (1 - cot A)2
cosec2 A . cosec2 B
(cot A - cot B)2 + (1 + cot A cot B)2 is equal to :
sec2 A - cos2 A
sec2 A - cosec2 A
(1 + tan A)2 - (1 - cot A)2
cosec2 A . cosec2 B