added function.split for simplify_exponential_function

src/main/py/read_math_function.py

@@ -78,3 +78,4 @@ def simplify_exponential_function(type, function):
         return False
     if 'x' not in function:
         return "Der Ausdruck muss die Variable 'x' enthalten."
+    coefficient, exponent = function.split('x^')