1.
已知二次函数\(f(x)=ax^{2}+bx+c(a,b,c∈R)\)对任意实数\(x\),都有\(x\leqslant f(x)\leqslant \dfrac {1}{4}(x+1)^{2}\)恒成立.
\((\)Ⅰ\()\)证明:\(f(1)=1\);
\((\)Ⅱ\()\)若\(f(-1)=0\),求\(f(x)\)的表达式;
\((\)Ⅲ\()\)在题\((\)Ⅱ\()\)的条件下设\(g(x)=f(x)- \dfrac {m}{2}x\),\(x∈[0,+∞)\),若\(g(x)\)图象上的点都位于直线\(y=- \dfrac {3}{4}\)的上方,求实数\(m\)的取值范围.