作者mikk (小禹~Guitar Fan)
看板GMAT
标题Re: [计量] PP-PS1
时间Sun Aug 24 16:52:03 2008
※ 引述《minimumi (米尼)》之铭言：
: For a finite sequence of nonzero numbers, the number of variations
: in sign is defined as the number of pairs of consecutive terms of
: the sequence for which the product of the two consecutive terms is
: negative. What is the number of variations in sign for the sequence
: 1, -3, 2, 5, -4, -6 ?
: (A) One
: (B) Two
: (C) Three
: (D) Four
: (E) Five
: 想请问这题该怎麽解~
: 谢谢
画图万能!
由以下图可知
因为正副号转变的次数 = 经过0那条线的次数 = 3
选(C)
有错误请指教 多谢 ^^
5 ●
/ \
4 / \
/ \
3 / \
/ \
2 ● \
/ \
1 ● / \
\ / \
0 --------------------------------------------------------------
\ / \
-1 \ / \
\ / \
-2 \ / \
\ / \
-3 ● \
\
-4 ●
\
-5 \
\
-6 ●
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1F：推 minimumi:谢谢你的解答~ 08/24 20:09