分式化简,求值要注意两点:
(1)乘法公式(或者因式分解)经常要用,比如通分,化简什么的,
(2)递等式计算准确性很重要.
试举一例:若a+m²=2004,①
b+m²=2003,②c+m²=2002,③
且abc=24,求a/bc+b/ca+c/ab-1/a-1/b-1/c=(1/8)
①-②:a-b=1,
②-③:b-c=1,
①-③:a-c=2
a/bc+b/ca+c/ab-1/a-1/b-1/c
=(a²+b²+c²-bc-ac-ab)/abc
=1/2[(a-b)²+(b-c)²+(c-a)²]/abc
=1/2(1²+1²+2²)24
=3/24
=1/8.