Difference between revisions of "2017 UNM-PNM Statewide High School Mathematics Contest II Problems/Problem 3"

(Created page with " == Problem == Let <math>f(x)=\frac{x}{x-1}</math> and <math>g(x)=\frac{x}{3x-1}</math>. (a) Determine <math>f\circ g(x)</math> and <math>g\circ f(x)</math>. (b) Denote...")
 
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Determine all the functions in the set <math>S = \{H | H = (g\circ f)^n\circ g</math> or <math>H = (f\circ g)^n\circ f</math> for some <math>n</math> a whole number<math>\}</math>.  
 
Determine all the functions in the set <math>S = \{H | H = (g\circ f)^n\circ g</math> or <math>H = (f\circ g)^n\circ f</math> for some <math>n</math> a whole number<math>\}</math>.  
 
== Solution==
 
== Solution==
 
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<math>S=\Big\{ \frac{x}{(2n+1)x-1} | n\in \mathbb{Z} \Big \} </math>
 
 
  
 
== See also ==
 
== See also ==

Latest revision as of 03:58, 19 January 2019


Problem

Let $f(x)=\frac{x}{x-1}$ and $g(x)=\frac{x}{3x-1}$.

(a) Determine $f\circ g(x)$ and $g\circ f(x)$.

(b) Denote $\underbrace{h\circ h\circ \cdot \circ h}_\text{n times} := h^n$. Determine all the functions in the set $S = \{H | H = (g\circ f)^n\circ g$ or $H = (f\circ g)^n\circ f$ for some $n$ a whole number$\}$.

Solution

$S=\Big\{ \frac{x}{(2n+1)x-1} | n\in \mathbb{Z} \Big \}$

See also

2017 UNM-PNM Contest II (ProblemsAnswer KeyResources)
Preceded by
Problem 2
Followed by
Problem 4
1 2 3 4 5 6 7 8 9 10
All UNM-PNM Problems and Solutions