题目内容
若n为正整数,关于x的方程x2-(2n+2003)x+n2an=0的两个根为αn,βn,且
+
=
,则a2003=______.
| 1 |
| αn |
| 1 |
| βn |
| 3 |
| n |
根据根与系数的关系,得αn+βn=2n+2003,αnβn=n2an.
又
+
=
,则
=
,即
=
,
把n=2003代入上式,得
=
,解得a2003=
=1.
又
| 1 |
| αn |
| 1 |
| βn |
| 3 |
| n |
| αn+βn |
| αnβn |
| 3 |
| n |
| 2n+2003 |
| n2an |
| 3 |
| n |
把n=2003代入上式,得
| 2•2003+2003 |
| 20032•a2003 |
| 3 |
| 2003 |
| 2×2003+2003 |
| 3×2003 |
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