4分之1x²-6x+3=0 用公式法解
a=1/4 ,b=-6 ,c=3
△=b²-4ac
=(-6)²-4×1/4×3
=36-3
=33
√△=√33
x=(-b±√△)/(2a)
=(6±√33)/(1/2)
=12±2√33
x1=12+2√33 ,x2=12-2√33
4分之1x²-6x+3
=(1/4)x²-6x+3
=(1/4)(x²-24x)+3
=(1/4)(x²-24x+12²)+3-12²×1/4
=(1/4)(x-12)²-33
当x=12时,有最小值-33
4分之1x²-6x+3=0 用公式法解
a=1/4 ,b=-6 ,c=3
△=b²-4ac
=(-6)²-4×1/4×3
=36-3
=33
√△=√33
x=(-b±√△)/(2a)
=(6±√33)/(1/2)
=12±2√33
x1=12+2√33 ,x2=12-2√33
4分之1x²-6x+3
=(1/4)x²-6x+3
=(1/4)(x²-24x)+3
=(1/4)(x²-24x+12²)+3-12²×1/4
=(1/4)(x-12)²-33
当x=12时,有最小值-33