a, \(\sqrt{24\cdot x^2\cdot y^2}\left(x\ge0\right)\)
b, \(\sqrt{24\cdot x^2\cdot y^2}\left(x\ge0\right)\)
\(\sqrt{18x}-\sqrt{200x}+7\sqrt{18x}+28\left(x\ge0\right)\)
giải hệ phương trình :
a) \(\hept{\begin{cases}x\cdot\left(1+y-x\right)=-2\cdot y^2-y\\x\cdot\left(\sqrt{2\cdot y}-2\right)=y\cdot\left(\sqrt{x-1}-2\right)\end{cases}}\)
b) \(\hept{\begin{cases}1+x\cdot y+\sqrt{x\cdot y}=x\\\frac{1}{x\cdot\sqrt{x}}+y\cdot\sqrt{y}=\frac{1}{\sqrt{x}}+3\cdot\sqrt{y}\end{cases}}\)
Làm hộ mk nhé mk tick cho :))))))))))
\(a=x\cdot y+\sqrt{\left(1+x^2\right)\cdot\left(1+y^2\right)}\) \(b=x\cdot\sqrt{1+y^2}+y\cdot\sqrt{1+x^2}\) với xy>0 tính b theo a
\(\hept{\begin{cases}a^2=x^2y^2+\left(1+x^2\right)\left(1+y^2\right)+2xy\sqrt{\left(1+x^2\right)\left(1+y^2\right)}\\b^2=y^2\left(1+x^2\right)+x^2\left(1+y^2\right)+2xy\sqrt{\left(1+x^2\right)\left(1+y^2\right)}\end{cases}}\)
\(\Rightarrow a^2-b^2=1\)
\(\Rightarrow a^2=1+b^2\)
Tính
\(\dfrac{1}{x-y}\cdot\sqrt{x^4\left(x-y\right)^2}\) (x>y)
\(\sqrt{27}\cdot\sqrt{48\cdot\left(2-a\right)^2}\) (a>2)
\(\left(\sqrt{2012}+\sqrt{2011}\right)\cdot\left(\sqrt{2012}+\sqrt{2011}\right)\)
\(\sqrt{\dfrac{64x^2}{49\left(y+1\right)^2}}\) (x<0;y>-1)
\(\sqrt{\dfrac{121x^2}{144\left(y+2\right)}}\left(x>0;y< -2\right)\)
\(\sqrt{\dfrac{676x^3}{169xy^2}}\left(x>0;y< 1\right)\)
a: \(=\dfrac{1}{x-y}\cdot x^2\cdot\left(x-y\right)=x^2\)
b: \(=\sqrt{27\cdot48}\cdot\left|a-2\right|=36\left(a-2\right)\)
c: \(=\left(\sqrt{2012}+\sqrt{2011}\right)^2\)
d: \(=\dfrac{8}{7}\cdot\dfrac{-x}{y+1}\)
e: \(=\dfrac{11}{12}\cdot\dfrac{x}{-y-2}=\dfrac{-11x}{12\left(y+2\right)}\)
rút gọn:
A=\(\dfrac{\sqrt{a}+\sqrt{b}}{\sqrt{a}-\sqrt{b}}-\dfrac{\sqrt{a^3}-\sqrt{b^3}}{a-b}\left(a,b\ge0,a\ne b\right)\)
B=\(\left(\dfrac{\sqrt{x^3}+\sqrt{y^3}}{\sqrt{x}+\sqrt{y}}-\sqrt{xy}\right)\cdot\left(\dfrac{\sqrt{x}+\sqrt{y}}{x-y}\right)\left(x,y\ge0,x\ne y\right)\)
cho số thực x,y không ậm và thỏa mãn điều kiện:\(x^2+y^2\le2\).hãy tính giá trị lớn nhất của biểu thức:
\(P=\sqrt{x\cdot\left(29\cdot x+3\cdot y\right)}+\sqrt{y\cdot\left(29\cdot y+3\cdot x\right)}\)
Cho mk hỏi con này ra bao nhiu z: \(A=\frac{\left(\sqrt{x}+2\right)\cdot\left(x-1\right)-\left(\sqrt{x}-2\right)\cdot\left(x+1\right)\cdot\left(x+1\right)}{\left(x+1\right)^2\cdot\left(x-1\right)}\)
Cho A=\(\left(\frac{\sqrt{x}-2}{x-1}-\frac{\sqrt{x}+2}{x+2\cdot\sqrt{x}+1}\right)\cdot\frac{\left(1-x\right)^2}{2}\) (với \(x\ge0\)và \(x\ne1\))
a, Rút gọn A
b, Tìm x để A>0
c, Tìm GTLN của A
\(A=\left(\frac{\sqrt{x}-2}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}-\frac{\sqrt{x}+2}{\left(\sqrt{x}+1\right)^2}\right).\frac{\left(1-x\right)^2}{2}\)
\(A=\left(\frac{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}{\left(\sqrt{x}+1\right)^2\left(\sqrt{x}-1\right)}-\frac{\left(\sqrt{x}+2\right)\left(\sqrt{x}-1\right)}{\left(\sqrt{x}+1\right)^2\left(\sqrt{x}-1\right)}\right).\frac{\left(1-x\right)^2}{2}\)
\(A=\left(\frac{x-\sqrt{x}-2-x-\sqrt{x}+2}{\left(\sqrt{x}+1\right)^2\left(\sqrt{x}-1\right)}\right).\frac{\left(1-x\right)^2}{2}\)
\(A=\frac{2}{\left(\sqrt{x}+1\right)^2.\left(\sqrt{x}-1\right)}.\frac{\left(1+\sqrt{x}\right)^2\left(\sqrt{x}-1\right)^2}{2}\)
\(A=\sqrt{x}-1\)
ý b,c dễ rồi nha
Thu gọn các đơn thức sau, xác định hệ số, phần biến và bậc của đơn thức
A=\(\left(\dfrac{-3}{7}\cdot x^3\cdot y^2\right)\cdot\left(\dfrac{-7}{9}\cdot y\cdot z^2\right)\cdot\left(6\cdot x\cdot y\right)\)
B= \(-4\cdot x\cdot y^3\cdot\left(-x^2\cdot y\right)^3\cdot\left(-2\cdot x\cdot y\cdot z^3\right)^2\)
HELP ME
\(A=\left(\dfrac{-3}{7}.x^3.y^2\right).\left(\dfrac{-7}{9}.y.z^2\right).\left(6.x.y\right)\)
\(A=\left(\dfrac{-3}{7}x^3y^2\right).\left(\dfrac{-7}{9}yz^2\right).6xy\)
\(A=\left(\dfrac{-3}{7}.\dfrac{-7}{9}.6\right).\left(x^3.x\right)\left(y^2.y.y\right).z^2\)
\(A=2x^4y^4z^2\)
\(B=-4.x.y^3\left(-x^2.y\right)^3.\left(-2.x.y.z^3\right)^2\)
\(B=\left[\left(-4\right).\left(-2\right)\right].\left(x.x^6.x^2\right)\left(y^3.y^3.y^2\right)\left(z^6\right)\)
\(B=8x^7y^{y^8}z^6\)