Update src/8_many_atoms_sol.md

src/8_many_atoms_sol.md

@@ -89,6 +89,8 @@ Both $v_g$ and $m_{eff}$ can be calculated using the respective formulae given i
 We know $g(E) = \frac{dN}{dk} \frac{dk}{dE} = \frac{L}{2\pi} \frac{1}{v_g}$ with $v_g$ from the previous subquestion. Graphically the density of states looks accordingly:
 
 ```python
+pyplot.figure()
+pyplot.title('Density of states for 2 atom unit cell and 1 atom unit cell')
 pyplot.subplot(1,3,1)
 k = np.linspace(-2*pi, 2*pi, 400)
 t1 = 1;