So sanh S=\(\frac{1}{5}+\frac{1}{9}+\frac{1}{10}+\frac{1}{40}+\frac{1}{42}voi\frac{1}{2}\)
minh can cach lam
ai nhanh minh tick
\(\left[\frac{31}{\left(2\frac{1}{3}\right):4}:\frac{31}{11}\right]\frac{1}{12}.x=\frac{1}{16}\)
minh can cach lam
ai nhanh minh tk
lop 6 thi cha chua hoc con gi nua
moi cap 1 con doi
Tim x
a) 3lx-2l+2x=19 , voi \(x\ge2\)
b)\(\frac{1}{5}< \frac{x}{30}< \frac{1}{4},\)voi \(x\in N\)
MINH CAN CACH LAM
AI NHANH MINH TK LUON
a) \(x\ge2\Leftrightarrow x-2\ge0\)
\(\Leftrightarrow\left|x-2\right|=x-2\)
\(3\left(x-2\right)+2x=19\)
\(\Leftrightarrow3x-6+2x=19\)
\(\Leftrightarrow5x=25\)
\(\Leftrightarrow x=5\)
b)\(\frac{1}{5}< \frac{x}{30}< \frac{1}{4}\)
\(\Leftrightarrow\frac{12}{60}< \frac{2x}{60}< \frac{15}{60}\)
Do \(x\in N\)nên ta có: \(\hept{\begin{cases}2x\in N\\2x⋮2\\12< 2x< 15\end{cases}}\)
\(\Rightarrow2x=14\)
\(\Leftrightarrow x=7\)
a) <=> 3x-6+2x=19
<=> 5x=25 => x=25:5=5
b) <=> 30/5<x<30/4 <=> 6< x < 7,5
x là số tự nhiên nên x=7
C = \(\frac{1+\frac{1}{3}+\frac{1}{3^2}+....+\frac{1}{3^{100}}}{1+\frac{1}{3}+......+\frac{1}{3^{101}}}\)
D = \(\frac{1+\frac{1}{3}+\frac{1}{3^2}+...+\frac{1}{3^{101}}}{1+\frac{1}{3}+........+\frac{1}{3^{102}}}\)
ai lam ho minh voi so sanh nha
\(M=\frac{1}{2}-\frac{1}{2^4}+\frac{1}{2^7}-\frac{1}{2^{10}}+......+\frac{1}{2^{\text{49}}}-\frac{1}{2^{52}}\)
so sanh m voi 9/4
nhờ giải đầy đủ nha ai làm đc mình tick cho\
BAi 1
a) hay so sanh
\(\frac{2014}{2015}+\frac{2015}{2014}\)va \(\frac{666665}{333333}\)
b)tinh
A=\(\left(1-\frac{1}{28}\right)\left(1-\frac{1}{36}\right)\left(1-\frac{1}{45}\right)...\left(1-\frac{1}{1326}\right)\)
cac ban lam nhanh nhe minh dang can gap xong minh tick cho
A)=vậy\(\frac{2014}{2015}+\frac{2015}{2014}>\frac{666665}{333333}.\)
bạn nhé
So sanh A va B biet: A=\(\frac{2010}{2011}+\frac{2011}{2012}+\frac{2012}{2010}\) va B=\(\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+...+\frac{1}{17}\)
Trinh bay cach lam cho minh voi nhe
Ai ko hieu thi vao phan "Doc them"
Giup minh voi nhe!Please
a)Cho S = \(\frac{1}{1!}+\frac{1}{2!}+\frac{1}{3!}+...+\frac{1}{2012!}.\) Chứng minh rằng S< 2
b)Chứng minh rằng :\(\frac{9}{10!}+\frac{10}{11!}+\frac{11}{12!}+\frac{99}{100!}< \frac{1}{9!}\)
Ai làm nhanh mk l*** cho nhé !
sửa đề : \(\frac{9}{10!}+\frac{10}{11!}+\frac{11}{12!}+...+\frac{99}{100!}\)
\(=\frac{10-1}{10!}+\frac{11-1}{11!}+\frac{12-1}{12!}+...+\frac{100-1}{100!}\)
\(=\frac{1}{9!}-\frac{1}{10!}+\frac{1}{10!}-\frac{1}{11!}+\frac{1}{11!}-\frac{1}{12!}+...+\frac{1}{99!}-\frac{1}{100!}\)
\(=\frac{1}{9!}-\frac{1}{100!}< \frac{1}{9!}\left(đpcm\right)\)
\(\frac{-1}{2}-\left(\frac{3}{2}+x\right)=-2\)\(2\)
NHANH NHA MINH DANH CAN GAP LAM,AI TRA LOI DUOC MINH CHO 10 TICK
\(\frac{-1}{2}\)\(-\left(\frac{3}{2}+x\right)=-22\)
\(\frac{-1}{2}\)\(-\frac{3}{2}\)\(-x=-22\)
\(-\left(\frac{1}{2}+\frac{3}{2}\right)-x=-22\)
\(-2-x=-22\)
\(x=-2-\left(-22\right)\)
\(x=20\)
không đúng thì thôi bạn đừng k sai nha!
Chứng minh
\(\frac{1}{41}+\frac{1}{42}+\frac{1}{43}+\frac{1}{44}+........................+\frac{1}{78}+\frac{1}{79}+\frac{1}{80}< \frac{1}{2}\)
Giúp mình nhé ai nhanh nhất mình tick
ta có \(\frac{1}{41}+\frac{1}{42}+...+\frac{1}{80}< \frac{1}{80}+\frac{1}{80}+..+\frac{1}{80}\)
ta có vế phải có 40 số , vế trái cũng có 40 số
VT=\(40\cdot\frac{1}{80}=\frac{40}{80}=\frac{1}{2}\)
do đó VT<1/2