已知向量a,b满足a,b=0,|a|=1,|b|=2,则|2a-b|=

问题描述:

已知向量a,b满足a,b=0,|a|=1,|b|=2,则|2a-b|=

|2a-b|^2
=4a^2-4ab+b^2
=4+4
=8
|2a-b|=2√2