已知向量a与b的夹角θ=120°,|a|=5,|b|=4:求|a-b|

2025-06-29 08:38:40
推荐回答(1个)
回答1:

|a-b|^2
=(5+4sin30°)^2+(4sin60°)^2
=49+12
=61
|a-b|=√61