Limit calculation rules:

• Expression: Mathematical function (e.g., x^2, sin(x), 1/x)
• Variable: Variable to be calculated (default: x)
• Approach: Value the variable approaches (number or ∞)
• Direction: Approaching from the right, left, or both sides

Examples:

• \[\lim_{x \to 0} \frac{\sin(x)}{x} = 1\]
• \[\lim_{x \to \infty} \frac{1}{x} = 0\]
• \[\lim_{x \to 1^+} \frac{1}{x-1} = \infty\]