cos^22x+sin^22x=1吗?

cos^22x+sin^22x=1吗? (1+cos x-sin x)/(1-sin x-cos x)+(1-cos x-sin x)/(1-sin x+cos x)=? 求证：cos3xcosx+sin^22x=sin3xsinx+cos^22x. 求证：cos3xcosx+sin^22x=sin3xsinx+cos^22x cos x/sin x+sin x/(1+cos x) 化简. sin（sin（sin（sin（x）=cos（cos（cos（cos（x）,X等于多少? cos x /sin x= 怎么证明2(1-sin x)(1+cos x)=(1-sin x+cos x)^2 y=(sin(x)-1)/(cos(x)+(cos(x))/(sin(x)+1)的奇偶性 求证（cos^2 x-sin^2 x)(cos^4 x+sin^4 x)+1/4 sin 2x sin 4x=cos 2x 为什么cos(sin(tan x)))=1 已知(1+sin x)/cos x=-1/2,则cos/(sin x-1)=? 求证：tan x/2=sin x/(1+cos x) 求证：1-sin(x)=cos(x)*tan(x/2) f'(sin x)=1-cos x 求f''(x) 1/cos(x) - tan(x) = 3 求sin(x)1/cos(x) - tan(x) = 3求sin(x) 已知函数f(x)=cos^4x-2cos^22x+sin^2x的最小正周期 为什么y = x - sin(x/2)cos(x/2) = x - (1/2)sin(x) 其中sin(x/2)cos(x/2)= (1/2)sin(x)是固定公式吗?