Simplify the following expression: $cosec^4A(1-cos^4 A) - 2 cot^2 A-1$
Answer & explanation
Correct answer: option 4
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