=>B<1/1.2+1/2.3+1/3.4+1/4.5+1/5.6+1/6.7+1/7.8
=>B<1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8
=>B<1-1/8=7/8<1
Vậy B<1
k cho mk nha
Bài 1:Chứng tỏ rằng:B=\(\dfrac{1}{2^2}\)+\(\dfrac{1}{3^2}\)+\(\dfrac{1}{4^2}\)+\(\dfrac{1}{5^2}\)+\(\dfrac{1}{6^2}\)+\(\dfrac{1}{7^2}\)\(\dfrac{1}{8^2}\)<1
Bài 2:Chứng tỏ rằng:E=\(\dfrac{3}{4}\)+\(\dfrac{8}{9}\)+\(\dfrac{15}{16}\)+...+\(\dfrac{2499}{2500}\)<1
Bài 3:Chứng tỏ rằng:1<\(\dfrac{2011}{2020^2+1}\)+\(\dfrac{2021}{2020^2+2}\)+\(\dfrac{2021}{2020^3+3}\)+...+\(\dfrac{2021}{2020^3+2020}\)< 2
Chứng tỏ rằng:B=1/22+1/32+1/42+1/52+1/62+1/72+1/82<1
Chứng tỏ rằng:B=\(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+\frac{1}{5^2}+\frac{1}{6^2}+\frac{1}{7^2}+\frac{1}{8^2}\)<1
chứng tỏ rằng:B=\(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+\frac{1}{5^2}+\frac{1}{6^2}+\frac{1}{7^2}+\frac{1}{8^2}<1\)
Chứng tỏ rằng:B=1+5+52+53+54+55+56+57+58
chứng tỏ răng:B=1/2^2+1/3^2+1/4^2=1/5^2+1/6^2 +1/7^2+1/8^2<1
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
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
Chứng tỏ rằng:B=1+5+52+53+54+55+56+57+58 chia hết cho 31