diff --git a/content/c2/s1/bayesian.md b/content/c2/s1/bayesian.md
index f8e0d45..8590a71 100755
--- a/content/c2/s1/bayesian.md
+++ b/content/c2/s1/bayesian.md
@@ -156,7 +156,7 @@ $$
 \begin{align}
 L(\bbetahat) &= \frac{1}{2}(\by - \bX\bbetahat)^\top(\by - \bX\bbetahat) + \frac{\lambda}{2}\bbetahat^\top \bbetahat 
 \\
-&= \frac{1}{2}(\by - \bX\bbetahat)^\top(\by - \bX\bbetahat) + \frac{\lambda}{2} \sum_{d = 0}^D\hat{\beta}_d.
+&= \frac{1}{2}(\by - \bX\bbetahat)^\top(\by - \bX\bbetahat) + \frac{\lambda}{2} \sum_{d = 0}^D\hat{\beta}_d^2.
 \end{align}
 $$
 
@@ -212,4 +212,4 @@ $$
 \bbetahat &= \left(\bX^\top\bSigma^{-1} \bX + \bT^{-1}\right)^{-1}\bX^\top\bSigma^{-1}\by \\
 &= \left(\frac{1}{\sigma^2}\bX^\top\bX + \frac{1}{\tau} I\right)^{-1}\frac{1}{\sigma^2}\bX^\top\by.
 \end{align*}
-$$
\ No newline at end of file
+$$