Cho A=100^2016+1/100^2015-1 và B=100^2015+1/100^2014-1
Trong 2 số A và B, số nào lớn hơn?
Giúp mình với nhé!
K
Khách
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Những câu hỏi liên quan
M
So sánh A và B
\(A=\frac{100^{2015}+1}{100^{2014}+1}\)
\(B=\frac{100^{2016}+1}{100^{2015}+1}\)
Gấp nha!
1
DH
2 tháng 3 2016
Ta có:
B>\(\frac{100^{2016}+1+99}{100^{2015}+1+99}\)=\(\frac{100^{2016}+100}{100^{2015}+100}\)=\(\frac{100\left(100^{2016}+1\right)}{100\left(100^{2015}+1\right)}\)=\(\frac{100^{2015}+1}{100^{2014}+1}\)=A
Vậy B>A
PN
10 tháng 5 2021
a,\(A=\frac{1}{5}+\frac{1}{5^2}+\frac{1}{5^3}+...+\frac{1}{5^{100}}\)
\(=>5A=1+\frac{1}{5}+\frac{1}{5^2}+...+\frac{1}{5^{99}}\)
\(=>5A-A=1-\frac{1}{5^{100}}=>A=\frac{1-\frac{1}{5^{100}}}{4}\)
b, Ta có \(1-\frac{1}{5^{100}}< 1=>\frac{1-\frac{1}{5^{100}}}{4}< \frac{1}{4}\)hay \(A< \frac{1}{4}\)
ML
14 tháng 6 2017
1.
a) \(\frac{6}{15}+\frac{6}{35}+\frac{6}{63}+\frac{6}{99}+\frac{6}{143}\)
\(=\frac{6}{3.5}+\frac{6}{5.7}+\frac{6}{7.9}+\frac{6}{9.11}+\frac{6}{11.13}\)
\(=\frac{6}{2}\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+...+\frac{1}{11}-\frac{1}{13}\right)\)
\(=\frac{6}{2}\left(\frac{1}{3}-\frac{1}{13}\right)\)
\(=\frac{6}{2}.\frac{10}{39}\)
\(=\frac{10}{13}\)
b) \(\frac{3}{24}+\frac{3}{48}+\frac{3}{80}+\frac{3}{120}+\frac{3}{168}\)
\(=\frac{3}{4.6}+\frac{3}{6.8}+\frac{3}{8.10}+\frac{3}{10.12}+\frac{3}{12.14}\)
\(=\frac{3}{2}\left(\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+\frac{1}{8}-\frac{1}{10}+...+\frac{1}{12}-\frac{1}{14}\right)\)
\(=\frac{3}{2}.\left(\frac{1}{4}-\frac{1}{14}\right)\)
\(=\frac{3}{2}.\frac{5}{28}\)
\(=\frac{15}{56}\)
14 tháng 6 2017
\(a.\frac{6}{3.5}+\frac{6}{5.7}+...+\frac{6}{11.13}\)
\(=3.\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{11}-\frac{1}{13}\right)\)
\(=3.\left(\frac{1}{3}-\frac{1}{13}\right)\)
\(=3.\frac{10}{39}\)
\(=\frac{10}{13}\)
17 tháng 3 2016
\(A=\frac{2014}{2015}+\frac{2015}{2016}>\frac{2014}{2016}+\frac{2015}{2016}>\frac{2014+1015}{2015+2016}=B\Rightarrow A>B\)
8 tháng 10 2018
Ta có : \(A=\frac{1}{1.2}+\frac{1}{3.4}+...+\frac{1}{99.100}\)
\(=1-\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{99}-\frac{1}{100}\)
\(=\left(1+\frac{1}{3}+...+\frac{1}{99}\right)-\left(\frac{1}{2}+\frac{1}{4}+...+\frac{1}{100}\right)\)
\(=\left(1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{99}+\frac{1}{100}\right)-2\left(\frac{1}{2}+\frac{1}{4}+...+\frac{1}{100}\right)\)
\(=\left(1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{99}+\frac{1}{100}\right)-\left(1+\frac{1}{2}+...+\frac{1}{50}\right)\)
\(=\frac{1}{51}+\frac{1}{52}+...+\frac{1}{100}\)
\(B=\frac{2015}{51}+\frac{2015}{52}+...+\frac{2015}{100}\)
\(=2015\left(\frac{1}{51}+\frac{1}{52}+...+\frac{1}{100}\right)\)
\(\Rightarrow\) \(\frac{B}{A}=\frac{2015\left(\frac{1}{51}+\frac{1}{52}+...+\frac{1}{100}\right)}{\frac{1}{51}+\frac{1}{52}+...+\frac{1}{100}}=2015\)
\(\Rightarrow\) \(B⋮A\)
\(A=\frac{100^{2016}+1}{100^{2015}-1}\)
\(\frac{1}{100}.A=\frac{100^{2016}+1}{100\left(100^{2015}-1\right)}\)
\(=\frac{100^{2016}+1}{100^{2016}-100}\)
\(=\frac{\left(100^{2016}-100\right)+101}{100^{2016}-100}\)
\(=\frac{100^{2016}-100}{100^{2016}-100}\)\(+\frac{101}{100^{2016}-100}\)
\(=1+\frac{101}{100^{2016}-100}\)
\(B=\frac{100^{2015}+1}{100^{2014}-1}\)
\(\frac{1}{100}.B=\frac{100^{2015}+1}{100\left(100^{2014}-1\right)}\)
\(=\frac{100^{2015}+1}{100^{2015}-100}\)
\(=\frac{\left(100^{2015}-100\right)+101}{100^{2015}-100}\)
\(=\frac{100^{2015}-100}{100^{2015}-100}\)\(+\frac{101}{100^{2015}-100}\)
\(=1+\frac{101}{100^{2015}-100}\)
\(\hept{\begin{cases}Vì101>0\\100^{2016}-100>100^{2015}-100>0\end{cases}}\)
\(\Rightarrow\frac{101}{100^{2016}-100}< \frac{101}{100^{2015}-100}\)
\(\Rightarrow1+\frac{101}{100^{2016}-100}< 1+\frac{101}{100^{2015}-100}\)
\(\Rightarrow\frac{1}{100}.A< \frac{1}{100}.B\)
\(\Rightarrow A< B\left(vì\frac{1}{100}>0\right)\)
Vậy A<B
cảm ơn cậu nhé!