TITLE: Prove existence of $c$ such that $f(x)\ge c g(x)$
QUESTION [7 upvotes]: Let $f$ and $g$ be non-negative continuous functions on $[0,1]$ such that $f(x)>g(x)$ for all $x$ in $[0,1]$. Show that there exists a constant $c>1$ such that for all $x$ in $[0,1]$ we have $f(x)\ge c g(x)$.
I tried using the fact that since $[0,1]$ is compact and $f$ and $g$ are continuous $f$ and $g$ each attain a maximum and a minimum on $[0,1]$, but it didn't get me anywhere. Anyone know how to prove this?

REPLY [4 votes]: Take $h(x)=\frac{g(x)}{f(x)}$. This function is continuous and well-defined because $f(x)>g(x)\geq 0$.
But the above says that $h(x)<1$ for all $x$. Then $h$ has a maximum, $m$ and it is less than $1$. We have that $\frac{g(x)}{f(x)}\leq m$ and therefore $m\cdot f(x)\geq g(x)$. Take $c=\frac1m$ then $c>1$ and we have $f(x)\geq c\cdot g(x)$.