已知a、b、c为实数,ab/a+b=1/6,bc/b+c=1/8,ca/c+a=1/10.求分式abc/ab+bc+ca的值.
问题描述:
已知a、b、c为实数,
=ab a+b
,1 6
=bc b+c
,1 8
=ca c+a
.求分式1 10
的值. abc ab+bc+ca
答
∵
=ab a+b
,1 6
=bc b+c
,1 8
=ca c+a
,1 10
∴
=6,a+b ab
=8,b+c bc
=10,c+a ca
∴
,
+ 1 b
=61 a
+1 c
=81 b
+1 a
=101 c
∴
=4,1 a
=2,1 b
=6,1 c
∴
+1 a
+1 b
=1 c
=12,bc+ac+ab abc
∴
=abc ab+bc+ca
.1 12