A:t2℃时,a,b,c三种物质的溶解度由大到小的顺序是a>b>c
B:t2℃时,将50g a物质放入100g水中充分溶解得到a的饱和溶液(a物质不含结晶水)
C:将t2℃时 a,b,c三种物质的饱和溶液降温至t1℃时,所得溶液溶质质量分数关系是b>a=c
D:将c的饱和溶液变为不饱和溶液,可采用升温的方法
已知向量m→=(2cosα,2sinα),n→=(3cosβ,3sinβ),若m→与n→的夹角为60°,则直线 xcosα-ysinα与圆(x-cosβ)2+(y+sinβ)2=12的位置关系是( )
Suggested questions:
①How is the earth becoming nowadays?
②What do you promise to do?
③What do you promise not to do?