Difference between revisions of "2020 AMC 12A Problems/Problem 10"

(Solution)
(Solution)
Line 7: Line 7:
 
becomes
 
becomes
  
<cmath>\log_2{\frac{1}{4}(\log_{2}{n})} = \frac{1}{2}\log_2{\frac{1}{2}(\log_2{n})}.</cmath>
+
<cmath>\log_2{\frac{1}{4}\log_{2}{n}} = \frac{1}{2}\log_2({\frac{1}{2}\log_2{n}}).</cmath>

Revision as of 10:28, 1 February 2020

Solution

Any logarithm in the form $\log_{a^b} c = \frac{1}{b} \log_a c$.

so \[\log_2{(\log_{2^4}{n})} = \log_{2^2}{(\log_{2^2}{n})}.\]

becomes

\[\log_2{\frac{1}{4}\log_{2}{n}} = \frac{1}{2}\log_2({\frac{1}{2}\log_2{n}}).\]