Show that the Jeans mass (Eq. 12.14) can also be written in the form
MJ=P01/2G3/2cJvT4(12.33)
where the isothermal sound speed, vT, is given by Eq. (12.18), P0 is the pressure associated with the density ρ0 and temperature T, and cJ≃5.46 is a dimensionless constant.