A:0N
B:12N
C:6N
D:无法确定
已知函数f(x)=sin(x+2φ)﹣2sinφcos(x+φ),则fπ4=____
20℃时,将等质量的甲、乙两种固体物质,分别加入到盛有100g水的烧杯中,充分搅拌后现象如图1,加热到50℃时,现象如图2,甲、乙两种物质的溶解度曲线如图3,请结合图示回答下列问题:
During the winter holiday, Ted learned ____ (skate) on the real ice.