Some corrections to Docs in buoyancy

Docs/sphinx_doc/theory/Buoyancy.rst

@@ -7,29 +7,6 @@
 
 .. _Buoyancy:
 
-Density of the mixture
-========================
-
-The total density in a given cell is given by
-
-.. math::
-    \rho = \frac{m}{V} = \frac{m_a + m_v + m_c + m_p}{V},
-
-where :math:`m_a` is the mass of dry air, :math:`m_v` is the mass of water vapor, :math:`m_c` is the mass of liquid water, and :math:`m_p` is the mass of precipitate.
-From the definitions of the mass mixing ratio (ratio of mass of a component to mass of dry air), we have for any component
-
-.. math::
-    q_i \equiv = \frac{m_i}{m_a}.
-
-Using this we can write
-
-.. math::
-    \rho = m_a\frac{(1 + q_v + q_c + q_p)}{V}
-          = \rho_d(1 + q_v + q_c + q_p),
-
-where :math:`\rho_d \equiv \cfrac{m_a}{V}` is the density of dry air.
-
-
 Buoyancy
 =========