有没有好办法?

 

Let N denote the number of 8-tuples (a_1, a_2, \dots, a_8) of real numbers such that a_1 = 10 and

\left|a_1^{2} - a_2^{2}\right| = 10

\left|a_2^{2} - a_3^{2}\right| = 20

\cdots

\left|a_7^{2} - a_8^{2}\right| = 70

\left|a_8^{2} - a_1^{2}\right| = 80

Determine the remainder obtained when N is divided by 1000.

 

先在此谢过。

所有跟帖: 

a2=110^.5, a3=90^.5, a4=60^.5, a5=10,a6=50^.5, a7=110^.5, a8=180 -jinjing- 给 jinjing 发送悄悄话 (65 bytes) () 12/31/2011 postreply 22:57:38

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