求证：（正弦平方减余弦平方）分之（正切平方减余切平方）等于正割平方分之余割平方

(tan^2x-cot^2x)/(sin^2x-cos^2x)
错!=csc^2x/sec^2x
csc^2x/sec^2x=(1/sin^2x)/(1/cos^2x)
=cos^2x/sin^2x
tan^2x-cot^2x=sin^2x/cos^2x-cos^2x/sin^2x
=(sin^4x-cos^4x)/(sin^2xcos^2x)
=(sin^2x+cos^2x)(sin^2x-cos^2x)/(sin^2xcos^2x)
=(sin^2x-cos^2x)/(sin^2xcos^2x)
(tan^2x-cot^2x)/(sin^2x-cos^2x)
=1/(sin^2xcos^2x)
=sec^2x*csc^2x