设向量a,b满足|a|=|b|=2,ab=-1⼀2,则|a+1⼀2b|=

2025-06-21 08:16:05
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回答1:

|a+b/2|^2=(a+b/2)·(a+b/2)=|a|^2+|b|^2/4+a·b=4+1-1/2=9/2
故:|a+b/2|=3sqrt(2)/2