8.
以下四个命题,其中正确命题的个数是( )
\(①\)若实数\(a,b,c\)满足\({{b}^{2}}=ac,\)则\(a,b,c\)成等比数列;
\(②\)定积分\(\int_{1}^{2}{\left( {{e}^{x}}+\dfrac{1}{x} \right)}dx\)的值为\({{e}^{2}}-e+\ln 2\);
\(③\)已知\(\alpha ,\beta \)是两个不重合的平面,\(l\)是一条直线,若\(\alpha ⊥\beta \),\(l ⊥\beta \),则\(l /\!/\alpha \);
\(④\)点\(P\)是\(\triangle ABC\)内一点,且\(\overrightarrow{AP}=\dfrac{1}{2}\overrightarrow{AB}+\dfrac{1}{3}\overrightarrow{AC},\)则\(\triangle ABP\)与\(\triangle ABC\)的面积之比为\(\dfrac{1}{3}\) .