Simplify the following expression: $cosec^4A(1-cos^4 A) - 2 cot^2 A-1$

$sin^2A$ $cosec^2A$ 1 0

0

cosec4A(1 - cos4A ) - 2cot2A - 1 = cosec4A(1 - cos2A )(1 + cos2A ) - cot2A- cot2A - 1  = cosec2A(1 + cos2A ) - cot2A - cosec2A { (1 - cos2A ) = sin2A & cot2A + 1  = cosec2A } = cosec2A + cot2A - cot2A - cosec2A = 0