2x2+\( \sqrt{1-x}+2x \sqrt{1-x^2}=1 \)
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a.
\(\Leftrightarrow2x^2\ge3\Leftrightarrow x^2\ge\dfrac{3}{2}\Rightarrow\left[{}\begin{matrix}x\ge\sqrt{\dfrac{3}{2}}\\x\le-\sqrt{\dfrac{3}{2}}\end{matrix}\right.\)
b.
\(\Leftrightarrow\left(1-x\right)\left(x-3\right)\ge0\Rightarrow1\le x\le3\)
c.
\(\Leftrightarrow\sqrt{1-3x}\le2-x\Leftrightarrow\left\{{}\begin{matrix}1-3x\ge0\\2-x\ge0\\1-3x\le x^2-4x+4\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\le\dfrac{1}{3}\\x\le2\\x^2-x+3\ge0\end{matrix}\right.\) \(\Leftrightarrow x\le\dfrac{1}{3}\)
c: ĐKXĐ: \(x\notin\left\{1;-1\right\}\)
d: ĐKXĐ: \(x\le1\)
\(a,PT\Leftrightarrow x^2-3x+2+x^2-x\sqrt{3x-2}=0\left(x\ge\dfrac{2}{3}\right)\\ \Leftrightarrow\left(x^2-3x+2\right)+\dfrac{x\left(x^2-3x+2\right)}{x+\sqrt{3x-2}}=0\\ \Leftrightarrow\left(x^2-3x+2\right)\left(1+\dfrac{x}{x+\sqrt{3x-2}}\right)=0\\ \Leftrightarrow\left(x-1\right)\left(x-2\right)\left(1+\dfrac{x}{x+\sqrt{3x-2}}\right)=0\)
Vì \(x\ge\dfrac{2}{3}>0\Leftrightarrow1+\dfrac{x}{x+\sqrt{3x-2}}>0\)
Do đó \(x\in\left\{1;2\right\}\)
\(b,ĐK:0\le x\le4\\ PT\Leftrightarrow x+2\sqrt{x}+1=6\sqrt{x}-3-\sqrt{4-x}\\ \Leftrightarrow x-4\sqrt{x}+4=-\sqrt{4-x}\\ \Leftrightarrow\left(\sqrt{x}-2\right)^2=-\sqrt{4-x}\)
Vì \(VT\ge0\ge VP\Leftrightarrow VT=VP=0\Leftrightarrow\left\{{}\begin{matrix}\sqrt{x}-2=0\\\sqrt{4-x}=0\end{matrix}\right.\Leftrightarrow x=4\left(tm\right)\)
Vậy PT có nghiệm \(x=4\)
a, \(y=f\left(x\right)=2x^2+1\)
\(f\left(-x\right)=2x^2+1=f\left(x\right)\Rightarrow\) Là hàm chẵn
b, \(y=f\left(x\right)=5x^3-2x\)
\(f\left(-x\right)=-5x^3+2x=-f\left(x\right)\Rightarrow\) Là hàm lẻ
c, \(y=f\left(x\right)=\sqrt{x-1}\)
ĐK: \(x\ge1\)
\(-f\left(x\right)=-\sqrt{x-1}\ne f\left(x\right)\Rightarrow\) Không phải là hàm số chẵn, lẻ
d, \(y=f\left(x\right)=5x^2-\dfrac{1}{x}\)
ĐK: \(x\ne0\)
\(f\left(-x\right)=5x^2+\dfrac{1}{x}\ne f\left(x\right)\)
\(-f\left(x\right)=-5x^2+\dfrac{1}{x}\ne f\left(-x\right)\)
\(\Rightarrow\) Không phải là hàm số chẵn, lẻ
a/ \(\lim\limits_{x\rightarrow-1}\dfrac{2x^3-5x-4}{\left(x+1\right)^2}=\dfrac{2.\left(-1\right)^3-5\left(-1\right)-4}{\left(-1+1\right)^2}=-\dfrac{1}{0}=-\infty\)
b/ \(\lim\limits\left(x^3+2\sqrt{x^5}-1\right)=\lim\limits x^3\left(1+0-0\right)=+\infty\)
giúp em câu này với ạ https://hoc24.vn/hoi-dap/tim-kiem?id=353722985710&q=lim%C2%A0\(\dfrac{1-\dfrac{1}{x}}{1+\dfrac{1}{x}}\)%C2%A0khi+x+ti%E1%BA%BFn+t%E1%BB%9Bi+0
`a)A=\sqrt{4+2sqrt3}`
`=\sqrt{3+2sqrt3+1}`
`=sqrt{(sqrt3+1)^2}`
`=sqrt3+1`
`B)1/(2-sqrt3)+1/(2+sqrt3)`
`=(2+sqrt3)/(4-3)+(2-sqrt3)/(4-3)`
`=2+sqrt3+2-sqrt3`
`=4`
`\sqrt{4x-12}+sqrtx{x-3}-1/3sqrt{9x-27}=8`
`đk:x>=3`
`pt<=>2sqrt{x-3}+sqrt{x-3}-sqrt{x-3}=8`
`<=>2sqrt{x-3}=8`
`<=>sqrt{x-3}=4`
`<=>x-3=16`
`<=>x=19`
Vậy `S={19}`
`a)A=\sqrt{4+2sqrt3}`
`=\sqrt{3+2sqrt3+1}`
`=sqrt{(sqrt3+1)^2}`
`=sqrt3+1`
`B)1/(2-sqrt3)+1/(2+sqrt3)`
`=(2+sqrt3)/(4-3)+(2-sqrt3)/(4-3)`
`=2+sqrt3+2-sqrt3`
`=4`
`\sqrt{4x-12}+sqrt{x-3}-1/3sqrt{9x-27}=8`
`đk:x>=3`
`pt<=>2sqrt{x-3}+sqrt{x-3}-sqrt{x-3}=8`
`<=>2sqrt{x-3}=8`
`<=>sqrt{x-3}=4`
`<=>x-3=16`
`<=>x=19`
Vậy `S={19}`
Ủa đáp số là\(\sqrt{2x-2}\) với \(\sqrt{2}\) mà bạn thử A2 đi