一條勁難既數學題

(x²+1)² - 4x²
=x^4+2x²+1-4x²
=x^4-2x²+1　／　=(x²-1)²
（是但一個）

2007-11-21 19:54:56 補充：
(x y)²=x² 2xy y²(x-y)²=x²-2xy y²E個係一條公式黎的

Factorize the following expression
(x^2+1)^2 - 4x^2
=[(x^2+1)- 2x][(x^2+1)+ 2x]
=(x^2- 2x+ 1)(x^2+2x+1)
=(x- 1)^2(x+1)^2
Yeah!!~

(x^2+1)^2-4x^2
=(x^2+1-2X)(x^2+1+2x)
=(x^2-2x+1)(x^2+2x+1)
=(x-1)^2(x+1)^2

(x^2+1)^2 - 4x^2
=[(x^2+1)- 2x][(x^2+1)+ 2x]
=(x^2- 2x+ 1)(x^2+2x+1)
=(x- 1)^2(x+1)^2