cho A=2/1.4/3....200/199 c/m rang 14<A<20
cho A=2/1.4/3....200/199 c/m rang 14<A<20
Cho A=2/1.4/3.6/5.8/7.....200/199.Chứng minh 14<A<20
helpppppppppppppppp
Vì :
2/1 > 14 => A > 14
20/199>20 => A>20
Cho E= 2/1.4/3....200/199
C/m 101< S.S < 400
Cho A=2/1.4/3.6/5.8/7.....200/199.Chứng minh 14<A<20.các anh cj khóa trên giúp vssssssssssssss
https://lazi.vn/edu/exercise/289338/cho-b-2-1-x-4-3-x-6-5-x-8-x-x-200-199-chung-minh-rang-14-lt-b-lt-20
Em xem tại link này nhé (Chị gửi cho)
Học tốt
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Cho A=2/1.4/3.6/5....200/199
c/n 101<S2<400
cho A=2/1.4/3.6/5.....200/199. Chứng minh rằng 201<A^2<400
A=1/2+3/4+5/6+........+199/200
chung to rang A^2<1/200
tinh A/B biet rang:
A=1/2+1/3+1/4+...+1/200
B =1/199+2/198+3/197+...+198/2+199/1
A=1/2+3/4+5/6+........+199/200
chung to rang A^2<1/201
3)
C= (1/2).(3/4).(5/6).....(199/200).
C= (1.3.5….199)/(2.4.6…200)
C²= 1².3².5²….199²/(2².4².6²…200²)
Ta có: k²>k²-1=(k-1)(k+1) nên 2²>1.3; 4²>3.5 … 200²>199.201.
=>
C² < 1².3².5²….199²/[(1.3).(3.5).(5.7)…(199.2...
=1².3².5²….199²/(1.3.3.5.5.7…199.201)
=1².3².5²….199²/(1.3².5².7²…199².201)
=1/201