(2cos^2x-1)/sin(x-π/4)=-根号2/2,cosx+sinx的值

化简(sin x+cos x-1)(sin x-cos x+1)/sin 2x 2cos x (sin x -cos x)+1 sin(x+1/2π)=cosx?还是cos-x 求证:(sin 2x /(1-cos 2x) )·(sin x /(1+sin x))=tan (π/4-x/2). 怎么证明2(1-sin x)(1+cos x)=(1-sin x+cos x)^2 化简 1/2cos x-根号3/2sin x 根3sin x+cos x 化简[1-(sin^4x-sin^2cos^2x+cos^4x)/(sin^2)]+3sin^2x 求证（cos^2 x-sin^2 x)(cos^4 x+sin^4 x)+1/4 sin 2x sin 4x=cos 2x sin^2(π+x)-cos(π+x)cos(-x)+1的值为 化简1+sin x/cos x·sin2x/2cos²（π/4-x/2） 求值sin²x+cos²(π/6+x)+1/2sin(2x+π/6) 化简2sin^2[(π/4)+x]+根号3（sin^x-cos^x）-1 已知-π/2＜x＜0,sin x+cos x=1/5求sin 2x+2 sin 已知sin[a-b]cos a-cos[b-a]sin a=3/5,b是第三象限角,求sin[b+5π/4]的值第一题1/2cos x-√3/2sin x第二题√3sin x+cos x第三题√2[sin x-cos x]第四题√2cos x-√6sin x 已知(1+sin x)/cos x=-1/2,则cos/(sin x-1)=? 已知tan=2,求(cos x+sin x)/(cos x-sin x)+sin^2x 求证：tan x/2=sin x/(1+cos x) 求证：1-sin(x)=cos(x)*tan(x/2)