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给出下列命题：
\(①\)若空间向量\( \overrightarrow{a}, \overrightarrow{b}{满足}| \overrightarrow{a}|=| \overrightarrow{b}|,{则} \overrightarrow{a}= \overrightarrow{b}\)
\(②\)空间任意两个单位向量必相等
\(③\)若空间向量\( \overrightarrow{a}, \overrightarrow{b}, \overrightarrow{c}{满足} \overrightarrow{a}\cdot \overrightarrow{c}= \overrightarrow{b}\cdot \overrightarrow{c},{则} \overrightarrow{a}= \overrightarrow{b}\)
\(④\)在正方体\(ABCD-A_{1}B_{1}C_{1}D_{1}\)中，必有\( \overrightarrow{BD}= \overrightarrow{B_{1}D_{1}}\)
\(⑤\)向量\( \overrightarrow{a}=(1,1,0)\)的模为\( \sqrt {2}\)；
其中假命题的个数是\((\) \()\)