Question

满足|x|+|y|≤4的整点(x,y)的个数是(　　)

A.16                     B.17                     C.40                     D.41

Answer 1

D

解析:

|x|=4时,y=0,有2个;|x|=3时,y=0,±1,有6个; |x|=2时,y=0,±1,±2,有10个;|x|=1时,y=0,±1,±2,±3,有14个;|x|=0时,?y=0,±1,±2,±3,±4,有9个,

∴共有2+6+10+14+9=41个,故选D.