题目: 计算sin4225°-cos4225°的值是( )A.12B.0C.-22D.2 答案: 由sin225°=sin(180°+45°)=-sin45°;cos225°=cos(180°+45°)=cos45°;化简原式=sin445°-cos445°=0故选B
题型:选择题 —Excuse me, do you have the time?— .A.Of course, I have B.No problemC.Yes, I doD.A quarter to ten 查看答案