1．
下列命题中：\(①\)若\(a > b\)，\(c\neq 0\)，则\(ac > bc\)；\(②\)若\(\dfrac{a}{b} < 0 \)，则\(a < 0\)，\(b > 0\)；\(③\)若\(ac^{2} > bc^{2}\)，则\(a > b\)；\(④\)若\(a < b < 0\)，则\(\dfrac{a}{b} > 1 \)；\(⑤\)若\(\dfrac{a}{{c}^{2}} > \dfrac{b}{{c}^{2}} \)，则\(a > b.\)正确的有\((\) \()\)个．