Update src/8_many_atoms_sol.md

src/8_many_atoms_sol.md

@@ -60,7 +60,7 @@ k = np.linspace(-2*pi, 2*pi, 400)
 pyplot.plot(k, np.sqrt(5+2*2*np.cos(k)),'b',label='2 atom dispersion')
 pyplot.plot(k, -np.sqrt(5+2*2*np.cos(k)),'b')
 pyplot.plot(k, -3*np.cos(k/2),'r',label='1 atom dispersion')
-pyplot.plot(k[199:-1:100],-3*np.cos(k[0:99]/2),'r--')
+pyplot.plot(k[199:100:-1],-3*np.cos(k[0:99]/2),'r--')
 
 pyplot.xlabel('$ka$'); pyplot.ylabel(r'$E-\epsilon$')
 pyplot.xticks([-2*pi, -pi, 0, pi,2*pi], [r'$-2ka$',r'$-ka$', 0, r'$ka$',r'$2ka$'])