如图,在△ABC中,∠C=90°,设∠A,∠B,∠C所对的边分别为a,b,c,则( )A.sinA= B.a=sinB×c C.cosA= D.tanA= 答案:【答案】C【解析】根据锐角三角函数的定义逐项进行判断即可.解:在△ABC中,∠C=90°,设∠A,∠B,∠C所对的边分别为a,b,c,因此有:sinA=,sinB=,cosA=,tanA=,故A不符合题意;故C符合题意;故D不符合题意;由sinB=可得b=sinB×c,故B不符合题意;故选:C. (上海卷40). Thai is the only way we can imagine the overuse of water in students' bathrooms. A. reducing B. to reduce C. reduced D. reduce