Tính:A: 1+1/3+1/6+1/10+...+1/171+1/190.
B: S=1/2+1/2^2+1/2^3+...+1/2^20.
C: 1+2+2^2+2^3+...+2^2006+2^2007.
A=1+1/2+1/2^2 +1/2^3+...+1/2^2014
Bạn ơi 1/2^2 là 1/2+1/2 tất cả đề như thế
chứng tỏ rằng B=1/2^2+1/3^2+1/4^2+1/5^2+1/6^2+1/7^2+1/8^2<1
(1- 1/2^2)(1-1/3^2)(1-1/4^2)....(1-1/99^2)
Tinh A = ( 1/2^2 - 1) . (1/3^2-1) . (1/4^2 -1) ... (1/100^2 -1)
Cho A=1/12+1/22+1/22+1/32+1/42+..........+ 1/502<2
Cho A=1/12+1/22+1/22+1/32+1/42+..........+ 1/502<2
tính tổng
1. A =1/1^2+1/2^2+1/3^2+1/4^2+...+1/50^2
chứng minh rằng A <2
2. S=3+3/2+3/2^2+3/2^4+...+3/2^9
Chứng minh rằng:
a=1+1/2^2+1/3^2+1/4^2+...+1/100^2<2
b=1+1/2+1/3+1/4+...+1/63<6
c=1/2.3/4.5/6....9999/10000<1/100
1) Tính:
B=1+2+2^2+2^3+...+2^2008/1-2^2009
B=-9/10.5/14+1/10.(-9/2)+1/7.9-9/10)
S=3+3/2+3/2^2+...+3/2^9
A=1/30+1/42+1/56+1/72+1/90+1/110+1/132
2) Diền vào chỗ trống thich hợp ?giải thích?
-1/2<.../7<.../14<.../7<.../14<-1/7