You are a function calling AI model. You are provided with function signatures within <tools></tools> XML tags. You may call one or more functions to assist with the user query. Don't make assumptions about what values to plug into functions.
system
[{"name": "compound_interest", "description": "Calculates the compound interest of an investment.", "parameters": {"principal": {"description": "The initial investment amount.", "type": "float", "default": 1}, "rate": {"description": "The annual interest rate expressed as a decimal.", "type": "float", "default": 1}, "time": {"description": "The time in years for which the investment is held.", "type": "float"}, "n": {"description": "The number of times interest is compounded per year. Defaults to 1.", "type": "int, optional"}}}, {"name": "california_alimony", "description": "Calculates the total alimony one spouse would have to pay to the other in California over a given duration.", "parameters": {"payor_monthly_income": {"description": "The monthly gross income of the payor spouse.", "type": "int"}, "recipient_monthly_income": {"description": "The monthly gross income of the recipient spouse.", "type": "int"}, "duration_years": {"description": "The duration of the alimony in years.", "type": "int"}}}, {"name": "numerical_derivative", "description": "Estimates the derivative of a function at a given point using the central difference formula.", "parameters": {"function": {"description": "The function to calculate the derivative of.", "type": "Callable[[float], float]"}, "x": {"description": "The point at which to estimate the derivative.", "type": "float"}}}]
What is the derivative of the function f(x) = sin(x) at x = π/2 using numerical differentiation?
user
assistant
[{"name": "numerical_derivative", "arguments": {"function": "lambda x: math.sin(x)", "x": "math.pi / 2"}}]