计算1-sin^2acos^2β+cos^2αsin^2β
化简:sin^2a+sin^2β-sin^2asin^2β+cos^2acos^2β
求证sin^4a+cos^4a=1-2sin²acos²a
化简:(1)sin(α+β)−2sinαcosβ2sinαsinβ+cos(α+β)
求证sin^2α+sin^2β-sin^2αsin^2β+cos^2cos^2β=1
化简sin^6a+cos^6+3sin^2acos^2a的结果是?
已知cos2a=(1/4),求cos^4a+sin^4+sin^2acos^2a的值
求证[1]1-2sin acos a/cos²a -sin²a =1-tan a/1+tan a.[
2.证明:sin²²a+cos²²a=1-2sin²acos²
sinα^2+sinβ^2+sinγ^2=1,那么cosαcosβcosγ最大值等于
急.三角函数:化简(sin^2a*cos^4a+sin^4acos^2a)/(1-sin^4a-cos^4a)
求证 sinαcosβ=1/2[sin(α+β)+sin(α-β)]
已知a(-0,兀且2SIN A-SIN ACOS A-3COS A=0求SIN(+兀/4)/SIN 2A+COS 2A+