Difference between revisions of "2014 UNM-PNM Statewide High School Mathematics Contest II Problems/Problem 2"

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(Solution 2)
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If <math>f(x) = x^3 + 6x^2 + 12x + 6</math>, solve the equation <math>f(f(f(x))) = 0.</math>
 
If <math>f(x) = x^3 + 6x^2 + 12x + 6</math>, solve the equation <math>f(f(f(x))) = 0.</math>
 
==Solution 2==
 
Note that <math>f(x)=(x+2)^3-2</math>. Thus, <math>f^{n}(x)=(x+2)^{3n}-2</math>. In the question, <math>n=3</math>, so we have <math>(x+2)^{27}-2=0</math>. Solving, <math>\boxed{x=-2+\sqrt[27]{2}}</math>
 
 
~yofro
 
  
 
== See also ==
 
== See also ==

Revision as of 01:15, 4 August 2020

Problem

If $f(x) = x^3 + 6x^2 + 12x + 6$, solve the equation $f(f(f(x))) = 0.$

See also

2014 UNM-PNM Contest II (ProblemsAnswer KeyResources)
Preceded by
Problem 1
Followed by
Problem 3
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All UNM-PNM Problems and Solutions