证明sin^4x-cos^4x=sin^2x-cos^2x

证明sin^4x-cos^4x=sin^2x-cos^2x 证明sin^2(x)+cos^2(x+30)+sin(x)cos(x+30)=3/4 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 sin^4+sin^2xcos^2x+cos^2x 证明 =1 求证明.关于cos和sin 题目有点长0 0【cos(2x) + cos(4x) + cos(6x)】 / 【sin(2x) + sin(4x) + sin(6x) 】 = cot(4x) 证明∫( 0,π／2 ) (f sin x/(f sin x+f cos x) dx=π /4 【高一数学】三角函数的证明题》》》》》》》证明：(sin^4)x+(sin^2)x(cos^2)x+(cos^2)x=1 求证（cos^2 x-sin^2 x)(cos^4 x+sin^4 x)+1/4 sin 2x sin 4x=cos 2x 怎么证明2(1-sin x)(1+cos x)=(1-sin x+cos x)^2 证明tan^θ-sin^2θ=tan^2θsin^2θ证明（1）tan^θ-sin^2θ=tan^2θsin^2θ（2）sin^4x+cos^4x=1-2sin^2cos^2x（31-tan^2x/1+tan^2x=cos^2x-sin^2x 求证sin^4x-cos^4x=sin^2x-cos^2x 化简sin^4x-sin^2x+cos^2x 化简:sin^4 x-sin^2 x+cos^2 x (sinX+sinθ) .(Sinx-sinθ)=sin(x+θ).cos(x-θ)证明 求证明：sin的4次方x＋cos的4次方x=1-2sin的2次方x乘cos的2次方x 证明：sin（π/4-x）=cos（π/4+x）