化简(x^3-1)/(x^3+2x^2+2x+1)+(x^3+1)/(x^3-2x^2+2x-1)-(2x^2+2)/(x^2-1) 方法：先化简再通分

化简(x^3-1)/(x^3+2x^2+2x+1)+(x^3+1)/(x^3-2x^2+2x-1)-(2x^2+2)/(x^2-1) 方法：先化简再通分
化简(x^3-1)/(x^3+2x^2+2x+1)+(x^3+1)/(x^3-2x^2+2x-1)-(2x^2+2)/(x^2-1) 方法：先化简再通分

化简(x^3-1)/(x^3+2x^2+2x+1)+(x^3+1)/(x^3-2x^2+2x-1)-(2x^2+2)/(x^2-1) 方法：先化简再通分
原式=(x-1)(x^2+x+1)/[(x+1)(x^2-x+1)+2x(x+1)]+(x+1)(x^2-x+1)/[(x-1)(x^2+x+1)-2x(x-1)]-2(x^2+1)/(x+1)(x-1)
=(x-1)(x^2+x+1)/(x+1)(x^2+x+1)+(x+1)(x^2-x+1)/(x-1)(x^2-x+1)-2(x^2+1)/(x+1)(x-1)
=(x-1)/(x+1)+(x+1)/(x-1)-2(x^2+1)/(x+1)(x-1)
=[(x-1)^2+(x+1)^2-2(x^2+1)]/(x+1)(x-1)
=(x^2-2x+1+x^2+2x+1-2X^2-2)/(x+1)(x-1)
=0