x^4-4x^2+4=(x²-2)²=(x+√2)²(x-√2)²
x^4-4x^2+4=(X^2-2)^2
(X^2-2)^2=(X+根号2)^2乘以(x-根号2)^2
饿是x^4-4x^2+4=(x^2-2)^2吧
x^4-4x^2+4=(x^2-2)^2