Ta có: \(\left(x-3.5\right)^2\ge0\forall x\)
\(\left(y-\dfrac{1}{10}\right)^4\ge0\forall y\)
Do đó: \(\left(x-3.5\right)^2+\left(y-\dfrac{1}{10}\right)^4\ge0\forall x,y\)
Dấu '=' xảy ra khi \(\left(x,y\right)=\left(\dfrac{7}{2};\dfrac{1}{10}\right)\)
do
\(\left(x-3.5\right)^2+\left(y-\dfrac{1}{10}\right)^4\ge0\)
mà ta có \(\left(x-3.5\right)^2+\left(y-\dfrac{1}{10}\right)^4\le0\)
nên \(\left(x-3.5\right)^2+\left(y-\dfrac{1}{10}\right)^4=0\)
suy ra \(\left\{{}\begin{matrix}x-3,5=0\\y-\dfrac{1}{10}=0\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=3,5\\y=\dfrac{1}{10}\end{matrix}\right.\)
tick mik nha
