Regex Tester & Validator

Matches implicit multiplication points in mathematical expressions, such as between a single digit and a letter (like '2x'), or between closing parentheses, variables (x, y, z), and subsequent alphanumeric characters or opening parentheses. It uses a negative lookahead to avoid matching multiple digits, and a positive lookahead to ensure a valid character follows. This regex is commonly used to format equations by inserting an explicit multiplication sign.