证明(tan^2x-cot^2x)/(sin^2x+cos^2x)=sec^2x+csc^2x

证明cot(x)-cot(x/2)=tan(x/2)+1拜托了各位 题目好像是,证明 cot(x)-cot(x/2)=tan(x/2)+1 或 证明 cot(x)-cot(x/2)=tan(x/2)-1.两者之一是对的,不记得了.大家来帮帮, 怎么证明tan^2x+cot^2x=2(3+cos4x)/1-cos4x 证明(tan^2x-cot^2x)/(sin^2x+cos^2x)=sec^2x+csc^2x 化简：cos^2x / ( cot(x/2)-tan(x/2) ) 化简：cos^2x / ( cot(x/2)-tan(x/2) ) lim x→0 (cot x)^tan 2x= 化简(1+cos2x)/{cot(x/2）-tan（x/2)} 设y=(tan^2 x-csc^2 x )/(tan^2 x+cot^2 x -1) (a)证明y=1- 2/(tan^4 x-tan^2 x +1) (b)求y值的范围 证明(tan^2x-cot^2x)/(sin^2x-cos^2x)=sec^2x+csc^2x^2=平方 证明(1+cot^2x)/(1-cot^2x)=1/(2sin^2x-1) 证明 cosx / (1-sinx) = ((cot x/2) +1 ) / ((cot x/2) - 1) 化简:sin(2派-x)tan(派+x)cot(-x-派)/tan(3派-x)cos(派-x) 求lim(x->0)(1+3(tan^2)x)^((cot^2)x) lim(x→0)(1+3tan^2(x))^cot^2(x)=? 化简tan（π-x）×cot（x-π）+cos²y-2cos²x 证明tanx-cotx=-2cot(2x) 证明(tan^2-sin^2)cot^2=sin^2 怎么证明tan^2A+cot^2A不等于1