Difference between revisions of "2014 AMC 12A Problems/Problem 24"

Revision as of 13:36, 9 February 2014

Let $f_0(x)=x+|x-100|-|x+100|$ , and for $n\geq 1$ , let $f_n(x)=|f_{n-1}(x)|-1$ . For how many values of $x$ is $f_{100}(x)=0$ ?

$\textbf{(A) }299\qquad \textbf{(B) }300\qquad \textbf{(C) }301\qquad \textbf{(D) }302\qquad \textbf{(E) }303\qquad$

1. Draw the graph of f_0(x) by dividing the domain into three parts.

2. Look at the recursive rule. Take absolute of the previous function and down by 1 to get the next function.

3. Count the x intercepts of the each function and find the pattern

(Revised by William Chi)

2014 AMC 12A (Problems • Answer Key • Resources)
Preceded by Problem 23	Followed by Problem 25
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25
All AMC 12 Problems and Solutions

@@ Line 13: / Line 13: @@
 . Look at the recursive rule. Take absolute of the previous  function and down by 1 to get the next function.
-. Count the x intercepts of the each function and find the pattern.
+. Count the x intercepts of the each function and find the pattern
+(Revised by William Chi)
 ==See Also==
 {{AMC12 box|year=2014|ab=A|num-b=23|num-a=25}}
 {{MAA Notice}}