diff --git a/README.md b/README.md
index 7ef422a..1809454 100644
--- a/README.md
+++ b/README.md
@@ -47,4 +47,4 @@ def calc_routh(self):
         print("SYSTEM IS UNSTABLE")
 ```
 ```calc_routh(self)``` as the core process of this class contains initialization and process about Routh Stability Process. Firstly, it define an empty zero (basically it filled with zeros) and iteratively being inserted by ```self.den``` (refering to Routh Table principle). After that, each cell will be updated by calculating Routh Table formula 
-$$  arr_{i,j} = \frac{arr_{i-1][0]*arr[i-2][j+1] - arr[i-2][0]*arr[i-1][j+1]}{arr_{i-1][0]} $$
+$ arr_{i,j} = \frac{arr_{i-1][0]*arr[i-2][j+1] - arr[i-2][0]*arr[i-1][j+1]}{arr_{i-1][0]} $