(2010•桂林二模)已知函数f(x)=ax3+[1/2]bx2-2x+c的图象在点(2,f(x))处的切线方程为4x-
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(Ⅰ)∵函数f(x)=ax3+12bx2-2x+c的图象在点(2,f(x))处的切线方程为4x-y-5=0∴f(2)=4×2-5=3,f′(2)=4∵函数f(x)在[-2,1)内单调递减,在[1,+∞)上单调递增∴函数f(x)在x=1处取得极小值,∴f′(...