Don't give up doing something if you have decided to do it.
A:agree
B:stop
C:keep
0.09____0.1
3.6____3.06
4.5____4.4
0.098____0.2
读“黄土高原示意图”,完成下列要求.
已知向量a→=cosθ,sinθ,向量b→=3,1,则2a→-b→的最大值和最小值分别为( )