问题
解答题
先化简,再求代数式的值.(
|
答案
原式=[
+2(a+1) (a-1)(a+1)
]•a-2 (a-1)(a+1) a-1 a
=
•2a+2+a-2 (a-1)(a+1) a-1 a
=
•3a (a-1)(a+1) a-1 a
=
,3 a+1
∵a=(-1)2013+tan60°=-1+
,3
∴原式=
=3 -1+
+13
.3
先化简,再求代数式的值.(
|
原式=[
+2(a+1) (a-1)(a+1)
]•a-2 (a-1)(a+1) a-1 a
=
•2a+2+a-2 (a-1)(a+1) a-1 a
=
•3a (a-1)(a+1) a-1 a
=
,3 a+1
∵a=(-1)2013+tan60°=-1+
,3
∴原式=
=3 -1+
+13
.3