2．
\((1)\)集合\(M=\{x∈N|x(x+2)\leqslant 0\}\)的子集个数为________．
\((2)\)函数\(y={{2}^{\frac{1}{x}}}\)的值域为________\(..\)
\((3)\) 若向量\(a=(1,0)\)，\(b=(2,1)\)，\(c=(x,1)\)满足条件\(3a-b\)与\(c\)共线，则\(x\)的值为________．
\((4)\) 当\(0 < x < \dfrac{π}{4}\)时，函数\(f(x)= \dfrac{\cos ^{2}x}{\cos x\sin x-\sin ^{2}x}\)的最小值是________．
\((5)\)电流强度\(I(\)安\()\)随时间\(t(\)秒\()\)变化的函数\(I=A\sin (ωt+φ)(A > 0,ω > 0,0 < φ < \dfrac{π}{2})\)的图像如图所示，则当\(t= \dfrac{1}{100}\) 秒时，电流强度是________．
