4.
下列命题正确的序号是
\(①\)命题“若\(a > b\),则\({{2}^{a}} > {{2}^{b}}\)”的否命题是真命题;
\(②\)若命题\(p:"\)\(\dfrac{1}{x-1} > 0 \)\("\),则;\(¬p \)\(:"\)\(\dfrac{1}{x-1}\leqslant 0 \)\("\);
\(③\)若\(p\)是\(q\)的充分不必要条件,则\(\neg p\)是\(\neg q\)的必要不充分条件;
\(④\)方程\(a{{x}^{2}}+x+a=0\)有唯一解的充要条件是\(a=\pm \dfrac{1}{2}\).