[理工] [線代]-subspaces
3.which of the following are subspaces of R∞?
(a) all sequences like (1,0,1,0,...) that include infinitely many zeros.
(b) all sequences (x1,x2,...) with xj=0 from some point onward.
(c) all decreasing sequences : xj+1≦xj for each j.
(d) all convergent sequences : the xj have a limit as j→∞.
(e) all geometric progressions (x1,kx1,k^2x1,...) allowing all k and
x1.
小弟認為這題答案應該是 a 跟 e 只有這兩個選項滿足子空間的定義
不知道大家的答案認為是多少
這題是台大期中考題
所以沒有正確答案
希望大家可以討論一下
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