deletions | additions       diff --git a/subsection_applying_information_theory_to__.tex b/subsection_applying_information_theory_to__.tex  index 35f586c..57becae 100644  --- a/subsection_applying_information_theory_to__.tex  +++ b/subsection_applying_information_theory_to__.tex 
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dP = dP_+ + dP_- \qquad {and} \qquad dU = dU_+ + dU_-  \]  then we can solve for the forward and backward pressure changes in terms of the measured changes $dP$ and $dU$  \[ $dP_\pm(t) = {\frac{1}{2}$} \big(dP(t) \pm \rho c dU(t)\big)$ \]  The changes in velocity follow from the water hammer equations. Thus, if we know the wave speed in the artery we can separate the measured changes in pressure into its forward and backward components.