求助一道数学题
四*** 2009-01-21 08:33:03 举报
x^4+4 =(x^2)^2+2^2+2*2*x^2-4x^2 =(x^2+2)^2-4x^2 =(x^2+2)^2-(2x)^2 =(x^2+2x+2)(x^2+2-2x)