Let $a,b,c,d$ be side of quadrilateral $ABCD$,prove or disprove
$$\dfrac{b}{a}+\dfrac{c}{b}+\dfrac{d}{c}+\dfrac{a}{d}\ge\dfrac{a+b+c+d}{\sqrt[4]{abcd}}$$
Let $a,b,c,d$ be side of quadrilateral $ABCD$,prove or disprove
$$\dfrac{b}{a}+\dfrac{c}{b}+\dfrac{d}{c}+\dfrac{a}{d}\ge\dfrac{a+b+c+d}{\sqrt[4]{abcd}}$$