a.b=-|a|.|b| tìm góc giữa hai vecto a ,b 30/11/2021 Bởi Remi a.b=-|a|.|b| tìm góc giữa hai vecto a ,b
$\overrightarrow{a}.\overrightarrow{b}=|a|.|b|.cos(\overrightarrow{a},\overrightarrow{b})\\ \overrightarrow{a}.\overrightarrow{b}=-|a|.|b|=>cos(\overrightarrow{a},\overrightarrow{b})=-1=>(\overrightarrow{a},\overrightarrow{b})=180^o$ Bình luận
$\overrightarrow{a}.\overrightarrow{b}=|a|.|b|.cos(\overrightarrow{a},\overrightarrow{b})\\ \overrightarrow{a}.\overrightarrow{b}=-|a|.|b|=>cos(\overrightarrow{a},\overrightarrow{b})=-1=>(\overrightarrow{a},\overrightarrow{b})=180^o$
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