changes.mady.by.user Arthur Aslanyan (Nafta College)
Saved on Mar 09, 2019
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p(t,r) = p_i + \frac{q_t}{4 \pi \sigma} {\rm Ei} \left(-\frac{r^2}{4 \chi t} \right)
p(t,r) \sim p_i + \frac{q_t}{4 \pi \sigma} \left[ \gamma + \ln \left(\frac{r^2}{4 \chi t} \right) \right] = p_i - \frac{q_t}{4 \pi \sigma} \ln \left(\frac{2.24585 \, t}{r^2} \right)