解答
展开 (a+b+c)4
解答
a4+4a3b+4a3c+4ac3+4bc3+4ab3+4b3c+6a2b2+6a2c2+6b2c2+c4+12a2bc+12abc2+12ab2c+b4
求解步骤
(a+b+c)4
化简 (a+b+c)4:(a+b+c)(a+b+c)(a+b+c)(a+b+c)
=(a+b+c)(a+b+c)(a+b+c)(a+b+c)
展开 (a+b+c)(a+b+c):a2+2ab+2ac+b2+2bc+c2
=(a2+2ab+2ac+b2+2bc+c2)(a+b+c)(a+b+c)
展开 (a2+2ab+2ac+b2+2bc+c2)(a+b+c):a3+3a2b+3a2c+3ac2+3bc2+3ab2+c3+3b2c+6abc+b3
=(a3+3a2b+3a2c+3ac2+3bc2+3ab2+c3+3b2c+6abc+b3)(a+b+c)
打开括号=a3a+a3b+a3c+3a2ba+3a2bb+3a2bc+3a2ca+3a2cb+3a2cc+3ac2a+3ac2b+3ac2c+3bc2a+3bc2b+3bc2c+3ab2a+3ab2b+3ab2c+c3a+c3b+c3c+3b2ca+3b2cb+3b2cc+6abca+6abcb+6abcc+b3a+b3b+b3c
化简 a3a+a3b+a3c+3a2ba+3a2bb+3a2bc+3a2ca+3a2cb+3a2cc+3ac2a+3ac2b+3ac2c+3bc2a+3bc2b+3bc2c+3ab2a+3ab2b+3ab2c+c3a+c3b+c3c+3b2ca+3b2cb+3b2cc+6abca+6abcb+6abcc+b3a+b3b+b3c:a4+4a3b+4a3c+4ac3+4bc3+4ab3+4b3c+6a2b2+6a2c2+6b2c2+c4+12a2bc+12abc2+12ab2c+b4
=a4+4a3b+4a3c+4ac3+4bc3+4ab3+4b3c+6a2b2+6a2c2+6b2c2+c4+12a2bc+12abc2+12ab2c+b4