Documentation typo (#2561)

* A small typo

* A small typo

* Mailmap

* A small typo

* A small typo

* Typo

* Update basicprinciples.rst

Removed the subscript as it was evident from the expression which variable the distribution is referred to.

docs/physics/montecarlo/basicprinciples.rst

@@ -95,8 +95,8 @@ Here, all scattering angles are equally likely. Thus, the corresponding
 
 .. math::
 
-    \rho_{\mu}(\mu) &= \frac{1}{2}\\
-    f_{\mu}(\mu) &= \frac{1}{2} (\mu - 1).
+    \rho(\mu) &= \frac{1}{2}\\
+    f(\mu) &= \frac{1}{2} (\mu + 1).
 
 This leads to the sampling rule
 
@@ -112,8 +112,8 @@ The probability of a photon interacting after covering an optical depth
 
 .. math::
 
-    \rho_{\tau}(\tau) &= \exp(-\tau)\\
-    f_{\tau}(\tau) &= 1 - \exp(-\tau).
+    \rho(\tau) &= \exp(-\tau)\\
+    f(\tau) &= 1 - \exp(-\tau).
 
 
 With the inverse transformation method, the optical depth to the next interaction location may then be sampled by 
@@ -127,4 +127,4 @@ which is equivalent to
 
 .. math::
 
-    \tau = - \mathrm{ln}z.
+    \tau = - \mathrm{ln}z.

docs/physics/montecarlo/propagation.rst

@@ -186,9 +186,9 @@ Thomson scattering is calculated by the formula
     \Delta \tau = \sigma_{\mathrm{T}} n_e l.
 
 The Thomson cross section :math:`\sigma_{\mathrm{T}}`, which is a constant,
-appears here. This corresponds to the fact that a packet has a probability of :math:`1-e^{\sigma_{\mathrm{T}} n_e l}`
+appears here. This corresponds to the fact that a packet has a probability of :math:`1-e^{-\sigma_{\mathrm{T}} n_e l}`
 of going through a Thomson scattering prior to traveling a distance :math:`l` (in other words, the probability of the
-packet making it across a distance :math:`l` without scattering is :math:`e^{\sigma_{\mathrm{T}} n_e l}`).
+packet making it across a distance :math:`l` without scattering is :math:`e^{-\sigma_{\mathrm{T}} n_e l}`).
 
 The situation is complicated by the inclusion of frequency-dependent
 bound-bound interactions, i.e. interactions with atomic line transitions.