Editing Mean motion (section)

===Mean motion and mean anomaly===
Mean motion also represents the rate of change of [[mean anomaly]], and hence can also be calculated,<ref>Vallado, David A. (2001). p. 54.</ref>
:<math>\begin{align}
n &= \frac{M_1 - M_0}{t_1 - t_0} = \frac{M_1 - M_0}{\Delta t}, \\
M_1 &= M_0 + n \times (t_1 - t_0) = M_0 + n \times \Delta t 
\end{align}</math>

where ''M''<sub>1</sub> and ''M''<sub>0</sub> are the mean anomalies at particular points in time, and &Delta;''t'' (&equiv; ''t''<sub>1</sub>-''t''<sub>0</sub>) is the time elapsed between the two.  ''M''<sub>0</sub> is referred to as the ''mean anomaly at [[Epoch (astronomy)|epoch]]'' ''t''<sub>0</sub>, and &Delta;''t'' is the ''time since epoch''.