(1+2/1)*(1+2/2)*(1+2/3)*(1+2/4)*..*(1+2/26)*(1+2/26)giúp mk vs nha mk đg cần gấp
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a: ĐKXĐ: x>=2
Ta có: \(4\sqrt{x-2}+\sqrt{9x-18}-\sqrt{\frac{x-2}{4}}=26\)
=>\(4\sqrt{x-2}+3\sqrt{x-2}-\frac12\cdot\sqrt{x-2}=26\)
=>\(6,5\cdot\sqrt{x-2}=26\)
=>\(\sqrt{x-2}=4\)
=>x-2=16
=>x=18(nhận)
b: ĐKXĐ: x∈R
\(3x+\sqrt{4x^2-8x+4}=1\)
=>\(3x+\sqrt{\left(2x-2\right)^2}=1\)
=>3x+|2x-2|=1
=>3x-1+|2x-2|=0(1)
TH1: x>=1
(1) sẽ trở thành: 3x-1+2x-2=0
=>5x-3=0
=>5x=3
=>x=3/5(loại)
TH2: x<1
(1) sẽ trở thành: 3x-1-2x+2=0
=>x+1=0
=>x=-1(nhận)
c: ĐKXĐ: x>=0
Ta có: \(\left(2\sqrt{x}+1\right)\left(\sqrt{x}-2\right)=7\)
=>\(2x-4\sqrt{x}+\sqrt{x}-2-7=0\)
=>\(2x-3\sqrt{x}-9=0\)
=>\(2x-6\sqrt{x}+3\sqrt{x}-9=0\)
=>\(\left(\sqrt{x}-3\right)\left(2\sqrt{x}+3\right)=0\)
=>\(\sqrt{x}-3=0\)
=>\(\sqrt{x}=3\)
=>x=9(nhận)
a,ĐKXĐ:\(x\ge2\)
\(4\sqrt{x-2}+\sqrt{9x-18}-\sqrt{\dfrac{x-2}{4}}=26\\ \Leftrightarrow4\sqrt{x-2}+3\sqrt{x-2}-\dfrac{\sqrt{x-2}}{2}=26\\ \Leftrightarrow8\sqrt{x-2}+6\sqrt{x-2}-\sqrt{x-2}=52\\ \Leftrightarrow13\sqrt{x-2}=52\\ \Leftrightarrow\sqrt{x-2}=4\\ \Leftrightarrow x-2=16\\ \Leftrightarrow x=18\left(tm\right)\)
b,ĐKXĐ:\(x\in R\)
\(3x+\sqrt{4x^2-8x+4}=1\\ \Leftrightarrow2\sqrt{x^2-2x+1}=1-3x\\ \Leftrightarrow\left|x-1\right|=\dfrac{1-3x}{2}\\ \Leftrightarrow\left[{}\begin{matrix}x-1=\dfrac{1-3x}{2}\\x-1=\dfrac{3x-1}{2}\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}2x-2=1-3x\\2x-2=3x-1\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{5}\left(tm\right)\\x=-1\left(tm\right)\end{matrix}\right.\)
c, ĐKXĐ:\(x\ge0\)
\(\left(2\sqrt{x}+1\right)\left(\sqrt{x}-2\right)=7\\ \Leftrightarrow\sqrt{x}\left(2\sqrt{x}+1\right)-2\left(2\sqrt{x}+1\right)=7\\ \Leftrightarrow2x+\sqrt{x}-4\sqrt{x}-2=7\\ \Leftrightarrow2x-3\sqrt{x}-9=0\\ \Leftrightarrow\left(2x+3\sqrt{x}\right)-\left(6\sqrt{x}+9\right)=0\\ \Leftrightarrow\sqrt{x}\left(2\sqrt{x}+3\right)-3\left(2\sqrt{x}+3\right)=0\\ \Leftrightarrow\left(\sqrt{x}-3\right)\left(2\sqrt{x}+3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}\sqrt{x}=3\\2\sqrt{x}=-3\left(vô.lí\right)\end{matrix}\right.\\ \Leftrightarrow x=9\left(tm\right)\)
\(\left(1-\frac{1}{2}\right)\cdot\left(1-\frac{1}{3}\right)\cdot\left(1-\frac{1}{4}\right)\cdot\left(1-\frac{1}{5}\right)\cdot...\cdot\left(1-\frac{1}{2017}\right)\cdot\left(1-\frac{1}{2018}\right)\)
\(=\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{3}{4}\cdot\frac{4}{5}\cdot...\cdot\frac{2016}{2017}\cdot\frac{2017}{2018}\)
\(=\frac{1\cdot2\cdot3\cdot4\cdot....\cdot2016\cdot2017}{2\cdot3\cdot4\cdot5\cdot....\cdot2017\cdot2018}\)
\(=\frac{1}{2018}\)