1道分式计算!!!急!!
http://hi.baidu.com/san%C9%A1/album/item/dd9da44b731833f182025c8e.html要有过程!!
做对再追加5分!
参考答案:是的,用立方和公式,拆得答案 -(1+x+x2)/(1+x)
=(x-x2-1)/(1-x)*(2-1-x3)/(1+x3)
=-[(x2-x+1)/(1-x)]*[(1-x)(1+x+x2)/(1+x)(1-x+x2)]
=-(1+x+x2)/(1+x)
http://hi.baidu.com/san%C9%A1/album/item/dd9da44b731833f182025c8e.html要有过程!!
做对再追加5分!
参考答案:是的,用立方和公式,拆得答案 -(1+x+x2)/(1+x)
=(x-x2-1)/(1-x)*(2-1-x3)/(1+x3)
=-[(x2-x+1)/(1-x)]*[(1-x)(1+x+x2)/(1+x)(1-x+x2)]
=-(1+x+x2)/(1+x)