(x+1)(x²+x/2+1)-(x+1/2)(x²+x+1)
=x³+3x²/2+3x/2+1-x³-3x²/2-3x/2-1/2
=1/2>0
所以(x+1)(x²+x/2+1)-(x+1/2)(x²+x+1)>0
所以(x+1)(x²+x/2+1)>(x+1/2)(x²+x+1)
(x+1)(x²+x/2+1)-(x+1/2)(x²+x+1)
=x³+3x²/2+3x/2+1-x³-3x²/2-3x/2-1/2
=1/2>0
所以(x+1)(x²+x/2+1)-(x+1/2)(x²+x+1)>0
所以(x+1)(x²+x/2+1)>(x+1/2)(x²+x+1)