Difference between revisions of "AoPS Wiki:Problem of the Day/September 19, 2011"
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Let <math>f(f(x))=x</math>, and let the point <math>(x,y)</math> and <math>(y,z)</math> are on the graph of <math>f(x)</math>. Which of the following must be true? | Let <math>f(f(x))=x</math>, and let the point <math>(x,y)</math> and <math>(y,z)</math> are on the graph of <math>f(x)</math>. Which of the following must be true? | ||
− | <math>\textbf{ (A)}f(x)=2f(z)\quad \textbf{(B)}x=f(z)\quad \textbf{(C)}f(x)=f(z) \quad \textbf{(D)}x=2y\quad \textbf{(E)}\text{None of the above}</math> | + | <math>\textbf{ (A)}f(x)=2f(z)\quad \textbf{(B)}x=f(z)\quad</math> <math> \textbf{(C)}f(x)=f(z) \quad \textbf{(D)}x=2y\quad \textbf{(E)}\text{None of the above}</math> |
Revision as of 16:16, 19 September 2011
Let , and let the point and are on the graph of . Which of the following must be true?