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Asked by  | 17th Sep, 2008, 07:19: PM

Expert Answer:

cot2A - tan2A = cos4A -sin4A / cos2A sin2A

multiply numerator and denominator by 4

4cos2A sin2A = sin22A

 cos4A -sin4A = (cos2A - sin2A)(cos2A +sin2A) = cos2A

cot2A - tan2A = cos4A -sin4A / cos2A sin2A  = 4cos2A / sin22A = 4cot2Acosec2A

Answered by  | 18th Sep, 2008, 01:07: PM

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