Skip to content / Đến nội dung
ThichHocToan.com

2014 AMC 12A Question 21

AMC12 · 2014 AMC 12A

Question 21

For every real number $x,$ let $\lfloor x\rfloor$ denote the greatest integer not exceeding $x,$ and let $$
f(x)=\lfloor x\rfloor\left(2014^{\,x-\lfloor x\rfloor}-1\right).
$$ The set of all numbers $x$ such that $1\le x\lt2014$ and $f(x)\le1$ is a union of disjoint intervals. What is the sum of the lengths of those intervals?
  1. $1$
  2. $\dfrac{\log2015}{\log2014}$
  3. $\dfrac{\log2014}{\log2013}$
  4. $\dfrac{2014}{2013}$
  5. $2014^{\frac{1}{2014}}$