Fx=ax^2+bx+1
F(-1)=a-b+1=0
对于任意函数均有Fx≥0
b^2-4a≤0
a>0
解得(a-1)^2≤0
a=1
b=2
Fx=x^2+2x+1
Gx=xFx-kx
=x^3+2x^2+(1-k)x
Gx'=3x^2+4x+1-k
Gx在[-1.2]为增函数,则Gx'在[-1.2]≥0
Fx=ax^2+bx+1
F(-1)=a-b+1=0
对于任意函数均有Fx≥0
b^2-4a≤0
a>0
解得(a-1)^2≤0
a=1
b=2
Fx=x^2+2x+1
Gx=xFx-kx
=x^3+2x^2+(1-k)x
Gx'=3x^2+4x+1-k
Gx在[-1.2]为增函数,则Gx'在[-1.2]≥0