tim A=√x+1/√x-1 CMR x=16/9 va x=25/9 thi A co gia tri nguyen
Những câu hỏi liên quan
cho bieu thuc A = 2012 / 9 - x . Voi gia tri nguyen cua x thi A co gia tri lon nhat ? Tim tri lon nhat do .
Bg
Ta có: A = \(\frac{2012}{9-x}\) (x \(\inℤ\); x \(\ne\)9) (x = 9 thì mẫu = 0, vô lý)
Để A lớn nhất thì 9 - x nhỏ nhất và 9 - x > 0
=> 9 - x = 1
=> x = 9 - 1
=> x = 8
=> A = \(\frac{2012}{9-x}=\frac{2012}{1}=2012\)
Vậy A đạt GTLN khi A = 2012 với x = 8
kết bạn với mình đi
a)Tim so nguyen x va y biet :
5/x+y/4=1/8
b)Tim so nguyen x de A co gia tri la 1 so nguyen biet :
A=(căn x +1) /(căn x -3) (x lớn hơn hoặc bằng 0)
b: Để A là số nguyên thì \(\sqrt{x}+1⋮\sqrt{x}-3\)
\(\Leftrightarrow\sqrt{x}-3+4⋮\sqrt{x}-3\)
\(\Leftrightarrow\sqrt{x}-3\in\left\{1;-1;2;-2;4\right\}\)
hay \(x\in\left\{16;4;25;1;49\right\}\)
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bai1 :P=x+2/x+3-5/(x+3)(x-2)+1/2-x
a,Tim dkxd cua P
b,Rut gon bieu thuc P
c,tim x de P=-3/4
d,tim gia tri nguyen cua x de P cung co gia tri nguyen
e,tinh gia tri bieu thuc P khi x^2-9=0
tim gia tri x nguyen de bieu thuc (3x2-4x+x-1)/(3x+2) co gia tri nguyen
tim gia tri x nguyen de bieu thuc (3x3-4x2+x+1)/(x-4) co gia tri nguyen
Cho f(x)=ax3+bx2+cx+d. CMR neu 6a, 2b, a+b+c va d la cac so nguyen to thi f(x) co gia tri nguyen voi moi so nguyen x
cho bieu thuc C =\(\left(\frac{x-\sqrt{x}}{\sqrt{x}-1}+1\right):\left(\frac{x+\sqrt{x}}{\sqrt{x}+1}\right)\)
a. tim dieu kien de C co nghia ?
b.rut gon C ?
c. tinh C tai x=\(\frac{4}{9}\)
d. tim x de C= 5
e.tim gia tri x nguyen de C co gia tri nguyen
Cho P = \(\left(\dfrac{1}{\sqrt{x}+1}-\dfrac{2\sqrt{x}-2}{x\sqrt{x}-\sqrt{x}+x-1}\right)\): \(\left(\dfrac{1}{\sqrt{x}-1}+\dfrac{2}{x-1}\right)\)
a/ Tim DKXD va rut gon P
b/ Tim cac gia tri nguyen cua x de P co gia tri nguyen
a ) ĐK : \(\left\{{}\begin{matrix}x\ge0\\x\ne1\end{matrix}\right.\)\(P=\left(\dfrac{1}{\sqrt{x}+1}-\dfrac{2\left(\sqrt{x}-1\right)}{\left(\sqrt{x}+1\right)^{^2}\left(\sqrt{x}-1\right)}\right):\left(\dfrac{1}{\sqrt{x}-1}+\dfrac{2}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}\right)\)
\(=\dfrac{x-1-2\sqrt{x}+2}{\left(\sqrt{x}+1\right)^2\left(\sqrt{x}-1\right)}:\dfrac{\sqrt{x}+3}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}\)
\(=\dfrac{\left(\sqrt{x}-1\right)^2}{\left(\sqrt{x}+1\right)^2\left(\sqrt{x}-1\right)}.\dfrac{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}{\sqrt{x}+3}\)
\(=\dfrac{\left(\sqrt{x}-1\right)^2}{\left(\sqrt{x}+1\right)\left(\sqrt{x}+3\right)}\)
\(=\dfrac{x-2\sqrt{x}+1}{x+4\sqrt{x}+3}\)
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Cho bieu thuc \(A=\left(\frac{x+1}{x-1}-\frac{x-1}{x+1}+\frac{x^2-4x-1}{x^2-1}\right).\frac{x+2016}{x}\)
a, Voi gia tri nguyen nao cua x thi bieu thuc A co gia tri nguyen
b,Voi gia tri nao cua x thi A co gia tri duong
tim gia tri nguyen cua m de hpt
\(3x-y=2m-1 va x+2y=3m-2\)
co nghiem (x;y) tm x^2 + 2y^2 = 9