怎么证明2(1-sin x)(1+cos x)=(1-sin x+cos x)^2

怎么证明2(1-sin x)(1+cos x)=(1-sin x+cos x)^2 怎么证明(1/2)sinx=sin(x/2)cos(x/2)怎么证明(1/2)sinx=sin(x/2)cos(x/2) 证明一个sin&cos的等式证明 1+sin^2(x)+sin^4(x)+sin^6(x)=[1-sin^8(x)]/[cos^2(x)] 证明：sin^2x+cos^2x=1 证明tan^2x-sin^2x=tan^2x*sin^2x解sin^2x sin^2x--------- - -----------cos^2x 1等于sin^2x sin^2x--------- - -----------cos^2c cos^2x+sin^2x接下来还能做吗?这道题还有其他证法吗?怎么能等式两边同除呢？这是证明题，证 (1+sinα^2)/cosα>1怎么证明(1+sinα^2)/cosα>1怎么证明上式恒成立? (cos X-1)^2+sin^2X=2-2cos X 证明题(要过程) 1-(sin^6x+cos^6x)=3sin^2xcos^2x 如何证明? 证明成立：[cos(3x)-sin(3x)]/(cosx+sinx)=1-2sin(2x). 证明1-sin^6x-cos^2x/1-sin^4x-cos^4x=3/2 一道三角函数证明题sin^4 X+cos^4 X=1-2sin^2 X cos^2 X 证明1-2sinxcosx/cos^2x-sin^2x=cos^2x-sin^2/1+2sinxcosx sin^4+sin^2xcos^2x+cos^2x 证明 =1 lim(sin(x^2*cos(1/x)))/x怎么做? 如何证明f(x)= sin[cos^(-1)x]是偶函数?f(x) =怎么证明这是偶函数? 如何证明sin方x+cos方x=1 证明|sin x|+|cos x|大于等于1 ....[1-(sin x)^2]^1/2=|cos x| 求证明........[1-(sin x)^2]^1/2=|cos x|求证明.....