Difference between revisions of "2012 AIME I Problems/Problem 9"
Line 10: | Line 10: | ||
<cmath> | <cmath> | ||
\begin{align*} | \begin{align*} | ||
− | 2\log_{x}(2y) = 2 &\ | + | 2\log_{x}(2y) = 2 &\implies x=2y\ |
− | 2\log_{2x}(4z) = 2 &\ | + | 2\log_{2x}(4z) = 2 &\implies 2x=4z\ |
− | \log_{2x^4}(8yz) = 2 &\ | + | \log_{2x^4}(8yz) = 2 &\implies 4x^8 = 8yz |
\end{align*} | \end{align*} | ||
</cmath> | </cmath> |
Revision as of 00:02, 9 February 2014
Problem 9
Let and be positive real numbers that satisfy The value of can be expressed in the form where and are relatively prime positive integers. Find
Solution
Since there are only two dependent equations given and three unknowns, the three expressions given can equate to any common value, so to simplify the problem let us assume with loss of generality that Then Solving these equations, we quickly see that and then Finally, our desired value is and thus
See also
2012 AIME I (Problems • Answer Key • Resources) | ||
Preceded by Problem 8 |
Followed by Problem 10 | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 | ||
All AIME Problems and Solutions |
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions.