Update 12_band_structures_in_higher_dimensions.md - typo

src/12_band_structures_in_higher_dimensions.md

@@ -40,7 +40,7 @@ How many electrons per unit cell can we expect for an insulator? To answer this
 
 For a single band
 
-$$ N_{states} = 2 \frac{L^3}{2\pi}^3 \int_{BZ} dk_x dk_y dk_z  = 2 L^3 / a^3 $$
+$$ N_{states} = 2 \frac{L^3}{(2\pi)^3} \int_{BZ} dk_x dk_y dk_z  = 2 L^3 / a^3 $$
 
 Here, $L^3/a^3$ is the number of unit cells in the system, so we see that a single band can host 2 electrons per unit cell (because of spin). If there are no overlapping bands, a system with 2 electrons per unit cell will therefore be an insulator/semiconductor.