Update app.py

app.py

@@ -38,6 +38,13 @@ request_history = deque(maxlen=1000)
 SYMPY_GUIDELINES = """
 When writing SymPy code to verify solutions:
 
+Import Guidelines:
+    - Either use specific imports like this:
+            from sympy import Matrix, solve, Symbol, pi, cos, sin
+    - OR use namespace import like this:
+            import sympy as sp
+But NEVER mix these import styles in the same code
+
 NOTE: For eigenvalue problems, use 'lam = Symbol('lam')' instead of importing from sympy.abc
 
 1. Variable Declaration and Expressions: