题目

在△ABC中,若b2sin2C+c2sin2B=2bccosBcosC,试判断三角形的形状. 答案：解:由正弦定理===2R(R为△ABC外接圆的半径),将原式化为8R2sin2Bsin2C=8R2sinBsinCcosBcosC.∵sinBsinC≠0,∴sinBsinC=cosBcosC,即cos(B+C)=0.∴B+C=90°,A=90°.故△ABC为直角三角形.说出下列句子的汉意。1. She is wearing a red scarf.___________________2. My windmill is moving slowly.___________________