分析:命题“若x
2-3x+2=0,则x=1”的逆否命题为:“若x≠1则x
2-3x+2≠0”;“A={x|x≤-2或x>1}”⇒“|x|>1”,“|x|>1”⇒“x≤-1或x>1}”;若
≠,则“•=•”不能推出“
=”,“
=”⇒“
•=•”,故若
≠,则“•=•”是“
=”的必要不充分条件;命题p:“?x∈R,使得x
2+x+1<0”,则?p:“?x∈R,均有x
2+x+1≥0”.
解答:解:命题“若x
2-3x+2=0,则x=1”的逆否命题为:“若x≠1则x
2-3x+2≠0”,故A正确;
“A={x|x≤-2或x>1}”⇒“|x|>1”,“|x|>1”⇒“x≤-1或x>1}”,故B正确;
若
≠,则“•=•”不能推出“
=”,“
=”⇒“
•=•”,
∴若
≠,则“•=•”是“
=”的必要不充分条件,故C错误;
命题p:“?x∈R,使得x
2+x+1<0”,则?p:“?x∈R,均有x
2+x+1≥0”,故D正确.
故选C.
点评:本题考查命题的真假判断与应用,是基础题.解题时要认真审题,仔细解答,注意向量知识和不等式知识的灵活运用.