03/15/17
Problem ✓  To show that
. re def of Wmif

him n = 0

n → no an If
.   =
;÷ , oljin
in ÷
, t.tt#i.l
= 9W
qn < = CI )

Fw 4.1 N
4ns 418
9
9
Few any E > 0 , E 112 and FE 7 0 , Thus , by The AP
ay ,
> 9
I k C IN sit. k > 0 .
YE
when men ,
n > 9 
4 E
⇒
4
4rad to
⇒ 9 < E t nzn cos
4h
a ) E (2) , we have . < E
combining  .
yn÷g nz of
n3
Thus , by The def . of www.t , wm  = ° .
ng
n→x Fn
let = m  the IN
Pyburn Xn Twilit
when n Is even : when w is odd :
.
Xn . n M¥114 xn . n  Fta
=  = n 
n (n41/z# €5 )

= 1/2 = 1/2
Tms =  FKG IN
, yzµ %
= 112 FKEIN .
Xyn .,
Since
Sol both {Xgµ} E { Xgn . } are convergent .
,
him = 
Xyn 11g F . =
ya x wnm→oX2n , 112 / { Un } must be divergent
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. whew NEK .
XNL %
let An =  Un the 1N .
nyn
An } is and
By , { con