化简sin^2α+sin^2β-sin^2cos^2β-cos^2αsin^2β
问题描述：
化简sin^2α+sin^2β-sin^2cos^2β-cos^2αsin^2β
答
sin^2α+sin^2β-sin^2αcos^2β-cos^2αsin^2β
=sin^2α(1-cos^2β)+sin^β(1-cos^2α)
=sin^2αsin^2β+sin^2βsin^2α
=2sin^2αsin^2β