Difference between revisions of "2011 AMC 12A Problems/Problem 21"

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== Problem ==
 
== Problem ==
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Let <math>f_{1}(x)=\sqrt{1-x}</math>, and for integers <math>n \geq 2</math>, let <math>f_{n}(x)=f_{n-1}(\sqrt{n^2 - x})</math>. If <math>N</math> is the largest value of <math>n</math> for which the domain of <math>f_{n}</math> is nonempty, the domain of <math>f_{N}</math> is <math>[c]</math>. What is <math>N+c</math>?
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<math>
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\textbf{(A)}\ -226 \qquad
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\textbf{(B)}\ -144 \qquad
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\textbf{(C)}\ -20 \qquad
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\textbf{(D)}\ 20 \qquad
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\textbf{(E)}\ 144 </math>
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== Solution ==
 
== Solution ==
 
== See also ==
 
== See also ==
 
{{AMC12 box|year=2011|num-b=20|num-a=22|ab=A}}
 
{{AMC12 box|year=2011|num-b=20|num-a=22|ab=A}}

Revision as of 01:36, 10 February 2011

Problem

Let $f_{1}(x)=\sqrt{1-x}$, and for integers $n \geq 2$, let $f_{n}(x)=f_{n-1}(\sqrt{n^2 - x})$. If $N$ is the largest value of $n$ for which the domain of $f_{n}$ is nonempty, the domain of $f_{N}$ is $[c]$. What is $N+c$?

$\textbf{(A)}\ -226 \qquad \textbf{(B)}\ -144 \qquad \textbf{(C)}\ -20 \qquad \textbf{(D)}\ 20 \qquad \textbf{(E)}\ 144$

Solution

See also

2011 AMC 12A (ProblemsAnswer KeyResources)
Preceded by
Problem 20
Followed by
Problem 22
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