MathDB
Minimum value of x/z - Iran First Round 2018, P19

Source:

March 7, 2021
inequalitiesalgebra

Problem Statement

Let xyzx \geq y \geq z be positive real numbers such that \begin{align*}x^2+y^2+z^2 \geq 2xy+2yz+2zx.\end{align*} What is the minimum value of xz\frac{x}{z}?
<spanclass=latexbold>(A)</span> 1<spanclass=latexbold>(B)</span> 2<spanclass=latexbold>(C)</span> 3<spanclass=latexbold>(D)</span> 2<spanclass=latexbold>(E)</span> 4<span class='latex-bold'>(A)</span>\ 1\qquad<span class='latex-bold'>(B)</span>\ \sqrt 2\qquad<span class='latex-bold'>(C)</span>\ \sqrt 3\qquad<span class='latex-bold'>(D)</span>\ 2\qquad<span class='latex-bold'>(E)</span>\ 4