题目

已知A、B、C是△ABC的内角，向量且。 （1）求角A的大小；（2）若，求tanC 。 答案：解： (1)因为且 所以-cosA+sinA=1,即sinA-cosA＝1所以2sin(A-)=1，sin(A-)= 因为AÎ(0,p),所以A-Î(-,),所以A-=,故A＝ (2)ÞÞ ÞcosB+sinB=-3cosB+3sinBÞ4cosB=2sinBÞtanB=2 tanC=tan(p-(A+B))=-tan(A+B) ==The variety of food at the restaurant is limited, but every meal can serve at least two people and is under 10, so not only is it ______ but practical as well.A. adaptable B. adjustableC. adoptable D. affordable