因为4x²-4x+2
=(2x-1)^2+1
而x=1/√(3)-1=[√(3)+1]/2
2x=√(3)+1
2x-1=√(3)
所以
4x²-4x+2
=(2x-1)^2+1
=(√(3))^2+1
=3+1
=4