Update 4.3-tutorial_py_thresholding.md

docs/4.0.0/4.3-tutorial_py_thresholding.md

@@ -143,8 +143,12 @@ $$
 其中：
 $$
 \begin{eqnarray*}
-q_1(t) = \sum_{i=1}^{t} P(i) \quad & \quad q_2(t) = \sum_{i=t+1}^{I} P(i) \\
-\mu_1(t) = \sum_{i=1}^{t} \frac{iP(i)}{q_1(t)} \quad & \quad \mu_2(t) = \sum_{i=t+1}^{I} \frac{iP(i)}{q_2(t)} \\
+q_1(t) = \sum_{i=1}^{t} P(i) \quad & \quad q_2(t) = \sum_{i=t+1}^{I} P(i)  
+$$  
+$$  
+\mu_1(t) = \sum_{i=1}^{t} \frac{iP(i)}{q_1(t)} \quad & \quad \mu_2(t) = \sum_{i=t+1}^{I} \frac{iP(i)}{q_2(t)}  
+$$
+$$
 \sigma_1^2(t) = \sum_{i=1}^{t} [i-\mu_1(t)]^2 \frac{P(i)}{q_1(t)} \quad & \quad \sigma_2^2(t) = \sum_{i=t+1}^{I} [i-\mu_2(t)]^2 \frac{P(i)}{q_2(t)}
 \end{eqnarray*}
 $$