下列结论错误命题的个数是
\(①\)若向量\(\overrightarrow{a}\parallel \overrightarrow{b}\),则存在唯一的实数\(λ\)使得\(\overrightarrow{a}{=}\lambda \overrightarrow{b}\);
\(②\)已知向量\(\overrightarrow{a}\),\(\overrightarrow{b}\)为非零向量,则“\(\overrightarrow{a}\),\(\overrightarrow{b}\)的夹角为钝角”的充要条件是“\(\overrightarrow{a}\cdot \overrightarrow{b} < 0\)”;
\(③\)“若\(\theta {=}\dfrac{\pi }{3}\),则\(\cos \theta {=}\dfrac{1}{2}\)”的否命题为“若\(\theta \ne \dfrac{\pi }{3}\),则\(\cos \theta \ne \dfrac{1}{2}\)”;
\(④\)若命题\(p:\exists {{x}_{0}}\in {R}\),\(x_{0}^{2}-x_{0}+1 < 0\),则\(\neg p:\forall x\in {R}\),\(x^{2}-x+1 > 0\);
\(⑤\)在\(\triangle ABC\)中,命题“\(\cos B=\sin A\)”是命题“\(\triangle ABC\)是直角三角形”的充要条件.