diff --git a/docs/5_atoms_and_lcao_solutions.md b/docs/5_atoms_and_lcao_solutions.md
index 6cd93be3b3365a7be9c84793dd14d97788b72820..e24b43950a6ff70607e5fa7c9f85c052afac7408 100644
--- a/docs/5_atoms_and_lcao_solutions.md
+++ b/docs/5_atoms_and_lcao_solutions.md
@@ -114,5 +114,5 @@ $$
 #### Question 4.
 We find the polarization using 
 $$
-P=2e\langle\psi|\hat{x}|\psi\rangle = 2e\left(\phi_1^2\langle 1|\hat{x}| 1 \rangle + \phi_1^2\langle 2|\hat{x}| 2 \rangle \right) = ed(\phi_2^2-\phi_1^2) =ed\frac{\eta}{1-\eta}
+P=2e\langle\psi|\hat{x}|\psi\rangle = 2e\left(\phi_1^2\langle 1|\hat{x}| 1 \rangle + \phi_2^2\langle 2|\hat{x}| 2 \rangle \right) = ed(\phi_2^2-\phi_1^2) =ed\frac{\eta}{1-\eta}
 $$