a^3-b^3=(a-b)(a^2+ab+b^2)
a^3+b^3=(a+b)(a^2-ab+b^2)
(a+b)^3=(a+b)^2*(a+b)
=(a^2+2ab+b^2)(a+b)
=a^3+2a^2b+ab^2+a^2b+2ab^2+b^3
=a^3+3a^2b+3ab^2+b^3
(a-b)^3=(a-b)^2*(a-b)=(a^2-2ab+b^2)*(a-b)=a^3-2a^2b+ab^2-a^2b+2ab^2-b^3=a^3-3a^2b+3ab^2-b^3
原创 | 2022-10-12 22:30:17 |浏览:1.6万
a^3-b^3=(a-b)(a^2+ab+b^2)
a^3+b^3=(a+b)(a^2-ab+b^2)
(a+b)^3=(a+b)^2*(a+b)
=(a^2+2ab+b^2)(a+b)
=a^3+2a^2b+ab^2+a^2b+2ab^2+b^3
=a^3+3a^2b+3ab^2+b^3
(a-b)^3=(a-b)^2*(a-b)=(a^2-2ab+b^2)*(a-b)=a^3-2a^2b+ab^2-a^2b+2ab^2-b^3=a^3-3a^2b+3ab^2-b^3