化简:sin^2αcos^2β-cos^2αsin^2β+cos^2α-cos^2β具体步骤,
问题描述：
化简:sin^2αcos^2β-cos^2αsin^2β+cos^2α-cos^2β具体步骤,
答
sin²acos²b-cos²asin²b+cos²a-cos²b
=(sin²a-1)cos²b-cos²a(1-sin²b)
=-cos²acos²b-cos²acos²b
=-2cos²acos²b
答
sin^2αcos^2β-cos^2αsin^2β+cos^2α-cos^2β
=sin^2αcos^2β-cos^2β-cos^2αsin^2β+cos^2α
=(sin^2α-1)cos^2β-cos^2α(sin^2β-1)
=-(1-sin^2α)cos^2β+cos^2α(1-sin^2β)
=-cos^2αcos^2β+cos^2αcos^2β
=0