(1+1/tan^2A) (1+1/cot^2A) = 1/cos^2-cos^4

1.	(1+1/tan^2A) (1+1/cot^2A) = 1/cos^2-cos^4
Answer» LHS=(1+1/tan²A).(1+1/cot²A)=(1+cot²A).(1+tan²A)=cosec²A.sec²A=1/(sin²A.cos²A)=1/{(1-cos²A)cos²A}=1/(cos²A-cos⁴A) = RHS(Proved)

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