changes.mady.by.user Arthur Aslanyan (Nafta College)
Saved on Mar 07, 2019
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p(t,xr) = p_i -+ \frac{q_t}{\sigma \, d} \bigg[ \sqrt{\frac{4 \chi t}{\pi}} \exp \bigg( -\frac{x^2}{4sigma} \chi, t} \bigg) - x \, Ei \bigg[( 1- {\rm erf} \bigg(\frac{xr^2}{\sqrt{4 \, \chi \, t}} \bigg) \bigg] \bigg]
p_{wf}(t) = p(t,x=0)= p_i -+ \frac{q_t}{4 \pi \sigma} \, d} \, \sqrt{\frac \bigg[ - 2S + Ei \bigg( - \frac{r_w^2}{4 \chi t}{\pi}} \bigg) \bigg]