给出以下命题: ①对于实数p和向量a,b,恒有p(a-b)=pa-pb; ②对于

发布时间：2017-04-13 01:51 │ 来源：www.tikuol.com

题型：填空题

问题：

给出以下命题:

①对于实数p和向量a,b,恒有p(a-b)=pa-pb;

②对于实数p,q和向量a,恒有(p-q)a=pa-qa;

③若pa=pb(p∈R),则a=b;

④若pa=qa(p,q∈R,a≠0),则p=q.

其中正确命题的序号为　　　.

考点：向量的概念及几何表示

题型：填空题

完形填空。

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