设α>β>0h/sinαsinβ*√（sin^α+sin^β-2sinαsinβcosαcosβ-2sin^αsin^β）=h/sinαsinβ*√（sin^α+sin^β-2sinαsinβcosαcosβ-sin^αsin^β-sin^αsin^β）=h/sinαsinβ*√（sin^α+sin^β-2sinαsin...