added cast to int for simplify_exponential_function

src/main/py/read_math_function.py

@@ -79,3 +79,5 @@ def simplify_exponential_function(type, function):
     if 'x' not in function:
         return "Der Ausdruck muss die Variable 'x' enthalten."
     coefficient, exponent = function.split('x^')
+    coefficient = int(coefficient) if coefficient else 1
+    exponent = int(exponent)