問題詳情
8.有一個51項的等差數列a1﹐a2﹐a3﹐…﹐a51﹐其和為0﹐且a31 = 31﹐則下列選項中哪些正確？
(A) a1 + a51 = 0
(B) a2 + a50 ＜ 0
(C) a3 + a49 ＞ 0
(D) a1 ＜ 0
(E) a21 = 21﹒
(A) a1 + a51 = 0
(B) a2 + a50 ＜ 0
(C) a3 + a49 ＞ 0
(D) a1 ＜ 0
(E) a21 = 21﹒
參考答案
答案：A,D
難度：非常困難0
統計：A(0),B(0),C(0),D(0),E(0)
內容推薦
- 【題組】(A)cutting down on(C) making sense of(B)giving rise to(D)tagging along with
- 【題組】(A)where (B)which(C) , on which (D)that
- 【題組】A new toll system for national freeways was _______ on December 30, 20Therevised rate ch
- 【題組】(A)thus made(C) thus making(B)this thus made(D)which thus making
- (F) The following is the storyline of the famous tragedy, Romeo and Juliet. The youngstar-crossed lo
- 【題組】(A)with (B)to(C) by (D)for
- 【題組】(A)produced (B)were producing(C) have produced (D)were to produce
- 【題組】To prevent overcrowding in the panda house when Yuanzai is put on its first public________,
- (E) Speaking of folk arts in Taiwan, glove puppetry is definitely something we can’tforget. However,
- 【題組】(A)make do with(C) end up nowhere near(B)take a back seat to(D)derive inspiration from
內容推薦
- 【題組】(A)as (B)yet(C) although (D)while
- (H) Tall buildings were originally designed with a specific goal in mind—to saveprecious urban land.
- 【題組】(A)leaving (B)to leave(C) to leaving (D)leave
- 【題組】甲﹑乙﹑丙﹑丁﹑戊﹑己﹑庚7人排成1列﹐求下列何者正確﹖ (A)甲﹑乙﹑丙完全相鄰方法數720種。 (B)甲﹑乙﹑丙完全分開方法數1440種。 (C)甲排首位或乙排2位方法數1320種。
- 下列有關化學式的敘述，何者正確？(A)乙炔的簡式為C2H2 (B)甲苯的分子式為C6H6(C)環己烷的分子式為C6H14 (D)順-2-丁烯與反-2-丁烯有相同的分子式。
- 【題組】(A)in cooperation with(C) at the disposal of(B)by means of(D)with the combination of
- 【題組】(A)horizontal (B)exceptional(C) occasional (D)vertical
- 【題組】(A)pushed for (B)tucked in(C) sprung up (D)turned to
- 【題組】(A)aroused (B)raised(C) rose (D)arose
- 下列敘述，何者錯誤？ (A)CH3COOH 與 C6H12O6 的簡式相同，而 CH3OCH3 與2H5OH 的分子式相同 (B)石墨、鑽石、C60 為同素異形體 (C)H2O2 是過氧化氫的簡
- (D)Poachers know that they can sell certain animal body parts for high sums, so theyhunt endangered
- 【題組】(A)In (B)On(C) At (D)By
- 【題組】(A)as it had plotted(C) as is plotted(B)as plotted(D)as having plotted
- 【題組】(A)takeoff (B)touchdown(C) undertone (D)breakthrough
- 【題組】When Rubber Duck was first ________ on Keelung Harbor, hundreds of passers-bygathered around
- 【題組】(A)on (B)for(C) to (D)with
- 【題組】(A)prone to (B)far from(C) subject to (D)nothing but
- 【題組】(A)as to (B)only to(C) yet (D)but
- 【題組】(A)one of them(C) and one of which(B)one such rule(D)one of which
- 【題組】People worldwide ________ Mandela’s death. Nelson Mandela, who died at 95 in2013, is the ico
- 【題組】(A)empty-handed(C) remote-controlled(B)record-smashing(D)far-reaching
- 【題組】一物體位於一凹面鏡前主軸上，物體離鏡頂 16 公分，經凹面鏡所成的像為一放大的實像。若物體向鏡頂移近 8 公分，則所成的像為一與之前的實像同大小的虛像。則下列敘述那些是正確的？(A)所成
- (G) Some companies are looking for more revolutionary ways to inspire innovation.However, striking a
- 【題組】(A)attracted (B)stimulated(C) appealed (D)fascinated
- 【題組】Though the right of gay lovers to live together should be respected, those opposingsame-sex