已知\(\left| {{\rm{ a }}} \right| = 1\)，\(\left| {{\rm{ b }}} \right| = -可可试卷app

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已知\(\left| {{\rm{ a }}} \right| = 1\)，\(\left| {{\rm{ b }}} \right| = \sqrt 2 \)，且\({\rm{a}} - {\rm{b}}\)与\(a\)垂直，则\(a\)与\({\rm{b}}\)的夹角为（）.

A.\(3{0}^{\circ }\)

B.\(6{0}^{\circ }\)

C.\({45}^{\circ }\)

D.\(9{0}^{\circ }\)

参考答案：C