1.展开式(x+a)(x+b)=x2+(a+b)x+ab(a±b)2=a2±2ab+b2(a±b)3=a3±3a2b+3ab2±b3(a+b+c)2=a2+b2+c2+2ab+2bc+2ca(a+b+c)3=a3+b3+c3+3a2b+3ab2 +3b2c+3bc2+3a2c+3ac2+6abca2-b2=(a-b)(a+b)a3±b3=(a±b)(a2∓ab+b2)a3+b3+c3-3abc=(a+b+c)(a2+b2+c2-ab-bc-ca)a4+a2b2+b4=(a2+ab+b2)(a (共 906 字) [阅读本文] >>