a-b=2x^4-2x^3-x^2+1
=2x^3(x-1)-(x+1)(x-1)
=(x-1)(2x^3-x-1)
=(x-1)(x^3-x+x^3-1)
=(x-1)[x(x+1)(x-1)+(x-1)(x^2+x+1)]
=(x-1)^2(x^2+x+x^2+x+1)
=(x-1)^2(2x^2+2x+1)
x不等于1,(x-1)^2>0
2x^2+2x+1=2(x^2+x)+1
=2(x^2+x+1/4-1/4)+1
=2(x^2+x+1/4)-2*1/4+1
=2(x+1/2)^2+1/2
2(x+1/2)^2>=0
所以2(x+1/2)^2+1/2>0
所以两个相乘大于0
所以a-b>0
a