S=1/3+2/3^2+3/3^3+4/3^4+..................+100/3^100. So sánh S với 1/5
Chứng mình `S<1/5`.
`S=1/3 - 2/(3^2) + 3/(3^3) - 4/(3^4) + ... +99/(3^99) - 100/(3^100)`
s=1-3+3^2-3^3+...+100/3^100 hãy so sánh s với 1/5
\(S=\dfrac{1}{3}+\dfrac{1}{3^2}+\dfrac{1}{3^3}+...+\dfrac{1}{3^{100}}\) so sánh S với \(\dfrac{1}{2}\)
S= 1/3 - 2/3^2 + 3/3^3 - 4/3^4+...+ 99/3^99 - 100/3^100
chứng minh S<1/5
mọi người giải giúp mik vs ạ
1.Tính tổng S=1/3+1/32+1/33+1/34+.....+1/399+1/3100
2.Tính tổng S=1+1/2+1/22+1/23+1/24+.....+1/299+1/2100
1.Tính tổng S=1/3+1/32+1/33+1/34+.....+1/399+1/3100
2.Tính tổng S=1+1/2+1/22+1/23+1/24+.....+1/299+1/2100
Chưng tỏ
a, S= 1/2^2+1/3^2+...+1/9^2
Chứng tỏ 2/5<S<8/9
b, 1/2-1/4+1/8-1/16+1/32-1/64<1/3
c, 1/3-2/3^2+3/3^3-4/3^4+...+99/3^99-100/3^100<3/16
S1 = 3/1 + 3/1+2 + 3/1+2+3 +...+3/1+2+3+...+100
S2 = 1/1.2.3 + 31/2.3.4 +...+1/1988.1999.2000
S3= 1/2.17 + 1/3.18 +1/4.19 +...+1/1990.2005
S1=1/2.1991+1/3.1992+...+1/16.2005
Chứng minh rằng : S3/S4=663/5