MathDB
Logarithmic Proof

Source: Canadian Repêchage 2010: Problem 1

May 6, 2014
logarithms

Problem Statement

Suppose that aa, bb and xx are positive real numbers. Prove that logabx=logaxlogbxlogax+logbx\log_{ab} x =\dfrac{\log_a x\log_b x}{\log_ax+\log_bx}.