Tìm x, biết:
2017+ 2016+ 2015+ ...+ ( x+1 )+ x= 2017 (x\(\in\) Z)
giúp mk vs cc bn ơi
Những câu hỏi liên quan
Tìm x,y,z biết
x + y = 1/2
y + z = 1/3
z + x = 1/4
các bn giúp mk vs mha nhanh lên
Tìm x, y, z biết \(\frac{x}{y+z+2016}=\frac{y}{x+z+2017}=\frac{z}{x+y-4033}=x+y+z\)
Tìm x, y, z biết \(\frac{x}{y+z+2016}=\frac{y}{x+z+2017}=\frac{z}{x+y-4033}=x+y+z\)
Tìm xin Z, biết: dfrac{1}{3}+dfrac{1}{6}+dfrac{1}{10}+...+dfrac{2}{x.left(x+1right)} dfrac{2014}{2016}
Cc bn ơi giúp mk vs mk đg rất gấp!!!!!!!
Đọc tiếp
Tìm x\(\in\) Z, biết: \(\dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{10}+...+\dfrac{2}{x.\left(x+1\right)}\) =\(\dfrac{2014}{2016}\)
Cc bn ơi giúp mk vs mk đg rất gấp!!!!!!!
\(=\dfrac{2}{2}\).(\(\dfrac{1}{3}\)+\(\dfrac{1}{6}\)+\(\dfrac{1}{10}\)+...+\(\dfrac{2}{x.\left(x+1\right)}\))
=2.(\(\dfrac{1}{6}\)+\(\dfrac{1}{12}\)+\(\dfrac{1}{20}\)+...+\(\dfrac{2}{x.\left(x+1\right)}\))
=2.(\(\dfrac{1}{2.3}\)+\(\dfrac{1}{3.4}\)+\(\dfrac{1}{4.5}\)+...+\(\dfrac{1}{x.\left(x+1\right)}\))
=2.[(\(\dfrac{1}{2}\)-\(\dfrac{1}{3}\))+(\(\dfrac{1}{3}\)-\(\dfrac{1}{4}\))+(\(\dfrac{1}{4}\)-\(\dfrac{1}{5}\))+...+(\(\dfrac{1}{x}\)-\(\dfrac{1}{x+1}\))
=2.[\(\dfrac{1}{2}\)-\(\dfrac{1}{3}\)+\(\dfrac{1}{3}\)-\(\dfrac{1}{4}\)+\(\dfrac{1}{4}\)-\(\dfrac{1}{5}\)+...+\(\dfrac{1}{x}\)-\(\dfrac{1}{x+1}\)]
2.[(\(\dfrac{1}{3}\)-\(\dfrac{1}{3}\))+(\(\dfrac{1}{4}\)-\(\dfrac{1}{4}\))+...+(\(\dfrac{1}{x}\)-\(\dfrac{1}{x}\))+(\(\dfrac{1}{2}\)-\(\dfrac{1}{x+1}\))]
=2.[0+0+...+0+(\(\dfrac{1}{2}\)-\(\dfrac{1}{x+1}\))]
=2.(\(\dfrac{1}{2}\)-\(\dfrac{1}{x+1}\))
=2.(\(\dfrac{1.x+1-1.2}{2.x+1}\))
=2.(\(\dfrac{x+1-2}{2x}\))=2.\(\dfrac{x-1}{2x}\)=\(\dfrac{2.\left(x-1\right)}{2x}\)=\(\dfrac{2x-2}{2x}\)
\(\dfrac{2x-2}{2x}\)=\(\dfrac{2014}{2016}\)\(\Rightarrow\)(2x-2).2016=2014.2x=4032x-4032=4028x
\(\Rightarrow\)4032x-4028x=4x=4032\(\Rightarrow\)x=4032:4=1008
Đúng 0
Bình luận (3)
Đặt A=\(\dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{10}+...+\dfrac{2}{x.\left(x+1\right)}\)
\(A=\dfrac{2}{6}+\dfrac{2}{12}+\dfrac{2}{20}+...+\dfrac{2}{x\left(x+1\right)}\)
\(A=\dfrac{2}{2.3}+\dfrac{2}{3.4}+\dfrac{2}{4.5}+...+\dfrac{2}{x.\left(x+1\right)}\)
Đúng 0
Bình luận (0)
mình làm mãi mệt waaaa!!!! tick mk nha cho ko tốn công mk 
Đúng 0
Bình luận (2)
\(\dfrac{\sqrt{x-2015}-1}{x-2015}\) + \(\dfrac{\sqrt{y-2016}-1}{y-2016}\) + \(\dfrac{\sqrt{z-2017}-1}{z-2017}\) = \(\dfrac{3}{4}\)
Đặt \(a=\sqrt{x-2015};b=\sqrt{y-2016};c=\sqrt{z-2017}\left(a,b,c>0\right)\)
Khi đó phương trình trở thành:
\(\dfrac{a-1}{a^2}+\dfrac{b-1}{b^2}+\dfrac{c-1}{c^2}=\dfrac{3}{4}\\ \Leftrightarrow\left(\dfrac{1}{4}-\dfrac{1}{a}+\dfrac{1}{a^2}\right)+\left(\dfrac{1}{4}-\dfrac{1}{b}+\dfrac{1}{b^2}\right)+\left(\dfrac{1}{4}-\dfrac{1}{c}+\dfrac{1}{c^2}\right)=0\\ \Leftrightarrow\left(\dfrac{1}{2}-\dfrac{1}{a}\right)^2+\left(\dfrac{1}{2}-\dfrac{1}{b}\right)^2+\left(\dfrac{1}{2}-\dfrac{1}{c}\right)^2=0\\ \Leftrightarrow a=b=c=2\\ \Leftrightarrow x=2019;y=2020;z=2021\)
Tick plz
Đúng 1
Bình luận (0)
tìm số nguyên x, y, z sao cho (x-y)^3+3(y-z)^2+|z-x|=2015
giúp mk vs nhé các bn
Các bn giúp mình với mình cảm ơn nhiều
1, tìm x thuộcZ biết
a,|x+1|+|x+2|=3x
b,154+153+....+x=154
c,(x+2017).(x-2018)=0
Mấy bn giải giúp mh Thanks nhiều!
Tìm các số nguyên x và y thỏa mãn: x^2015+x^2016+2015^2016=y^2016+y^2017+2016^2017
Tìm x , y biết rằng : | x - 2011 | + | x - 2013 | + | x - 2015 | + | y - 2017 | = 4
Ta có \(\left|x-2011\right|+\left|x-2015\right|=\left|-x+2011\right|+\left|x-2015\right|\ge4\),\(\hept{\begin{cases}\left|x-2013\right|\ge0\\\left|y-2017\right|\ge0\end{cases}}\)
\(\Rightarrow VT\ge4\). Dấu = xảy ra khi \(\hept{\begin{cases}\left(-x+2011\right).\left(x-2015\right)\ge0\\x-2013=0\\y-2017=0\end{cases}\Rightarrow\hept{\begin{cases}x=2013\\y=2017\end{cases}}}\)
Vậy ...
Đúng 0
Bình luận (0)