Update app.py

app.py

@@ -398,7 +398,7 @@ with tab1:
         st.markdown("""Enter expressions for s = numerator/denominator 
                     (using variables `y`, `beta`, `z_a`)""")
         st.latex(r"\text{This s will be inserted into:}")
-        st.latex(r"\frac{y\beta(z_a-1)\underline{s}+(a\underline{s}+1)((y-1)\underline{s}-1)}{(a\underline{s}+1)(\underline{s}^2 + \underline{s})}")
+        st.latex(r"\frac{y\beta(\text{z_a}-1)\underline{s}+(a\underline{s}+1)((y-1)\underline{s}-1)}{(a\underline{s}+1)(\underline{s}^2 + \underline{s})}")
         s_num = st.text_input("s numerator", value="y*beta*(z_a-1)", key="s_num")
         s_denom = st.text_input("s denominator", value="z_a", key="s_denom")