问题描述: 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 1个回答 分类:数学 2014-12-07 问题解答: 我来补答 (tan^2x-cot^2x)/(sin^2x-cos^2x)错!=csc^2x/sec^2xcsc^2x/sec^2x=(1/sin^2x)/(1/cos^2x)=cos^2x/sin^2xtan^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 展开全文阅读