Update solver.py

solver.py

@@ -28,8 +28,9 @@ def preprocess_equation(equation_str):
             'cos⁻¹': 'acos',
             'tan⁻¹': 'atan',
             'e^': 'exp',
-            'ln': 'log',
-            '!': 'factorial',
+            'ln': 'log',  # Convert ln to log (SymPy default)
+            '√': 'sqrt',  # Convert square root symbol to sqrt()
+            '!': '.factorial()',  # Convert factorial to function call
         }
         for old, new in replacements.items():
             equation_str = equation_str.replace(old, new)
@@ -83,11 +84,12 @@ def process_expression(expr_str):
             result = diff(expr, x)
             return f"d/dx({format_expression(expr)}) = {format_expression(result)}"
 
-        elif 'factorial' in processed_expr:  # Factorial
+        elif 'factorial' in processed_expr:  # Factorial case
             expr = parse_expr(processed_expr, transformations=(standard_transformations + (implicit_multiplication_application,)))
-            result = expr.doit()
+            result = expr.doit()  # Evaluate factorial properly
             return f"{format_expression(expr)} = {format_expression(result)}"
 
+
         elif '/' in expr_str:  # Handle fractions and return decimal
             expr = parse_expr(processed_expr, transformations=(standard_transformations + (implicit_multiplication_application,)))
             simplified = simplify(expr)