计算1/(a-b) +(3ab)/(b^3-a^3) -(a-b)/(a^2+ab+b^2)=?
參考答案:1/(a-b) +(3ab)/(b^3-a^3) -(a-b)/(a^2+ab+b^2)
=(a^2+ab+b^2)/(a^3-b^3)-3ab/(a^3-b^3)-(a-b)^2/(a^3-b^3)
=(a^2+ab+b^2-3ab-a^2+2ab-b^2)/(a^3-b^3)
=0
计算1/(a-b) +(3ab)/(b^3-a^3) -(a-b)/(a^2+ab+b^2)=?
參考答案:1/(a-b) +(3ab)/(b^3-a^3) -(a-b)/(a^2+ab+b^2)
=(a^2+ab+b^2)/(a^3-b^3)-3ab/(a^3-b^3)-(a-b)^2/(a^3-b^3)
=(a^2+ab+b^2-3ab-a^2+2ab-b^2)/(a^3-b^3)
=0