\(x^5-2023x^4-2023x^3-2023x^2-2023x-2010\)
tính giá trị biểu thức 1 cách hợp lí khi x =2024
Tính giá trị biểu thức:
A= x50-2023x49+2023x48-...+2023x2-2023x+2024 tại x = 2022
x=2022
=>x+1=2023
A=x^50-x^49(x+1)+x^48(x+1)-...+x^2(x+1)-x(x+1)+x+2
=x^50-x^50-x^49+x^49+...+x^3+x^2-x^2-x+x+2
=2
x + 3x + 5x + 7x + ... + 2023x = 2023 x 2024
x + 3x+ 5x +7x +..+2023x=2023 x 2024
Xét VT : x+3x+5x+7x+......+2023x
Số hạng của dãy số trên là : \(\dfrac{2023-1}{2}+1=1012\left(sốhạng\right)\)
Tổng số của dãy số trên là : \(\dfrac{\left(2023x+x\right).1012}{2}\text{=}1012x.1012\)
Do đó : ta có :
\(1012x.1012\text{=}2023.2024\)
\(1012x\text{=}4046\)
\(x\text{=}\dfrac{2023}{506}\)
VT = x + 3x + 5x + 7x +... + 2023x = [(2023 - 1):2 +1] . (2023+1)x = 1012. 2024x = 2048288x
VP= 2023 . 2024= 4094552
VT=VP <=> 2048288x =4094552
<=>\(x\approx2\)
tìm số tự nhiên a để biểu thức 2023x(10-a) có giá trị bé nhất
2023(10-a) min khi 10-a=0
=>a=10
Cho x, y, z thoả mãn xyz = 2023.
Chứng minh: \(\dfrac{2023x}{xy+2023x+2023}+\dfrac{y}{yz+y+2023}+\dfrac{z}{xz+z+1}=1\)
Có `xyz=2023=>2023=xyz`
Thay vào ta có :
\(\dfrac{xyz\cdot x}{xy+xyz\cdot x+xyz}+\dfrac{y}{yz+y+xyz}+\dfrac{z}{xz+z+1}=1\\ \dfrac{x^2yz}{xy\left(1+xz+z\right)}+\dfrac{y}{y\left(z+1+xz\right)}+\dfrac{z}{xz+z+1}=1\\ \dfrac{xz}{1+xz+z}+\dfrac{1}{z+1+xz}+\dfrac{z}{xz+z+1}=1\\ \dfrac{xz+1+z}{1+xz+z}=1\left(dpcm\right)\)
1/2023x 1/5 + 1/2023 x 8/5- 1/2023x16/20
`1/2023xx1/5+1/2023xx8/5-1/2023xx16/20`
`=1/2023xx(1/5+8/5-16/20)`
`=1/2023xx(1/5+8/5-4/5)`
`=1/2023xx5/5=1/2023`
Giải phương trình: \(\sqrt{1+\left(x+2\right)\sqrt{1+\left(x+3\right)\left(x+5\right)}}=2023x+1\)
ĐKXĐ : \(x\ge-2\)
\(\sqrt{1+\left(x+2\right).\sqrt{1+\left(x+3\right).\left(x+5\right)}}=2023x+1\)
\(\Leftrightarrow\sqrt{1+\left(x+2\right).\sqrt{x^2+8x+16}}=2023x+1\)
\(\Leftrightarrow\sqrt{1+\left(x+2\right).\left(x+4\right)}=2023x+1\) (Do \(x\ge-2\Rightarrow x+4>0\))
\(\Leftrightarrow\sqrt{x^2+6x+9}=2023x+1\)
\(\Leftrightarrow x+3=2023x+1\) (Do \(x\ge-2\Rightarrow x+3>0\)
\(\Leftrightarrow x=\dfrac{1}{1011}\)(tm)
Vậy tập nghiệm \(S=\left\{\dfrac{1}{1011}\right\}\)
0^2020x1^2021x2^2022 x 3^2023x..x21^2120
\(0^{2020}\cdot1^{2021}\cdot....\cdot21^{2120}=0\cdot1^{2021}\cdot...\cdot21^{2120}=0\)
(x+1/1.2)+(x+1/2.3)+(x+1/3.4)+....+(x+1/2022.2023)=2023x
\(\Rightarrow\left(x+x+...+x\right)+\left(\dfrac{1}{1.2}+\dfrac{1}{2.3}+\dfrac{1}{3.4}+...+\dfrac{1}{2022.2023}\right)=2023x\)
\(\Rightarrow2022x+\left(\dfrac{1}{1}-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{4}-...-\dfrac{1}{2021}+\dfrac{1}{2021}-\dfrac{1}{2022}+\dfrac{1}{2022}-\dfrac{1}{2023}\right)=2023x\)\(\Rightarrow2022x-2023x=-\left(1-\dfrac{1}{2023}\right)\)
\(\Rightarrow-x=-\dfrac{2022}{2023}\Leftrightarrow x=\dfrac{2022}{2023}\)
(x + 1/1.2) + (x + 1/2.3) + (x + 1/3.4) + ... + (x + 1/2022.2023) = 2023x
x + x + x + ... + x + 1/1.2 + 1/2.3 + ... + 1/2022.2023 = 2023x
2022x + 1 - 1/2 + 1/2 - 1/3 + ... + 1/2022 - 2023 = 2023x
2023x - 2022x = 1 - 1/2023
x = 2022/2023