mình ko biết mình làm đúng hay sai bạn nhé, mong mọi người góp ý
= 1/2.( 1/2.4+1/4.6+....+1/(2x-2)2x)=1/8
= 1/2.(1/2-1/4+1/4-1/6+....+1/(2x-2)-1/2x)=1/8
= 1/2.( 1/2-1/2x)=1/8
( 1/2-1/2x)=1/8:1/2
1/2-1/2x=1/4
1/2x =1/2-1/4
1/2x =1/4
2x = 4
x =4:2
x =2
1: \(\dfrac{2\cdot\left(x+2\right)}{3}-\dfrac{5\cdot\left(x-1\right)}{4}=\dfrac{3\cdot\left(5-x\right)}{2}-1\dfrac{1}{2}\cdot\left(2x+3\right)\)
\(Tìm\) \(x\)∈\(Z\)\(,\) \(biết\)\(:\)
\(a\)) \(\left(x-20\right)+\left(x-19\right)+\left(x-18\right)+...+99+100=100\)
\(b\)) \(213-x.\left(\dfrac{1}{2}+\dfrac{1}{2^2}+\dfrac{1}{2^3}+...+\dfrac{1}{2^{2020}}\right):\left(1-\dfrac{1}{2^{2020}}\right)=13\)
Tìm x :
a) \(\left|x+\dfrac{11}{17}\right|+\left|x+\dfrac{2}{17}\right|+\left|x+\dfrac{4}{17}\right|=4x\)
b) \(\left|x+\dfrac{1}{2}\right|+\left|x+\dfrac{1}{6}\right|+\left|x+\dfrac{1}{12}\right|+\left|x+\dfrac{1}{20}\right|+..+\left|x+\dfrac{1}{110}\right|=11x\)
tìm x biết :
1.\(\dfrac{-5}{6}+\dfrac{8}{3}+\dfrac{-29}{6}\le x\le\dfrac{-1}{2}+2+\dfrac{5}{2}\)
2.\(\left(2,7x-1\dfrac{1}{2}x\right):\dfrac{2}{7}=\dfrac{-21}{4}\)
3.\(\left|2x-\dfrac{3}{4}\right|=1\)
làm hộ mik 3 con này cái
Tìm giá trị nhỏ nhất :
\(D=\left|x-\dfrac{1}{2}\right|+\left|x-\dfrac{1}{3}\right|+\left|x-\dfrac{1}{4}\right|+...+\left|x-\dfrac{1}{2022}\right|\)
Bài 1: Tìm x,y biết:
a) \(\left|x-\dfrac{2}{3}\right|+\left|y+x\right|=0\) b) \(\left(x-2y\right)^2+\left|x+\dfrac{1}{6}\right|=0\)
c) \(\left|3x+5y\right|+\left|y-2\right|=0\)
Bài 2: Tìm giá trị nhỏ nhất
A= \(\left|5x+1\right|-\dfrac{3}{8}\) B= \(\left|2-\dfrac{1}{6}x\right|+0,25\)
Bài 3: Tìm giá trị lớn nhất
A= 2018 - \(\left|x+2019\right|\) B= -10 - \(\left|2x-\dfrac{1}{1009}\right|\)
Tìm x, biết:
a) \(\dfrac{3}{4.7}+\dfrac{3}{7.10}+....+\dfrac{3}{x\left(x+3\right)}=\dfrac{9}{38}\)
b) \(\dfrac{1}{21}+\dfrac{1}{28}+\dfrac{1}{36}+...+\dfrac{2}{x\left(x+1\right)}=\dfrac{2}{9}\)
Câu hỏi today là a, \(\dfrac{1}{5\cdot8}+\dfrac{1}{8\cdot11}+...+\dfrac{1}{x+\left(x+1\right)}=\dfrac{101}{1540}\)
b,\(\dfrac{1}{1\cdot2}+\dfrac{1}{2\cdot3}+\dfrac{1}{3\cdot4}+...+\dfrac{1}{x+\left(x+1\right)}=\dfrac{2020}{2021}\)
Chúc các bn học tốt ❤
Tính :
C = \(\left(1+\dfrac{1}{2.3}\right)\) \(\left(1+\dfrac{1}{2.4}\right)\) \(\left(1+\dfrac{1}{3.5}\right)\) .....\(\left(1+\dfrac{1}{2014.2016}\right)\)
