deletions | additions       diff --git a/Now_its_time_time.tex b/Now_its_time_time.tex  index de26b61..61a3bab 100644  --- a/Now_its_time_time.tex  +++ b/Now_its_time_time.tex 
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\end{equation}  where $c$ is a constant which we're going to determine. {\color{red}In practice, this equation is usually rearranged to give:  \begin{equation}  m = -2.5\log(f) -2.5\log_{10}(f)  + c. \end{equation}  Derive this form.} For two  sources, the difference in their magnitudes is then proportional to the  ratio of their fluxes:  \begin{equation}  \Delta m = m_1 - m_2 = 2.5 \log_{10} \left(frac{f_2}{f_1}\right) \left(\frac{f_2}{f_1}\right)  \label{eq:appmagfluxratio}  \end{equation}