The conversation between human and AI assistant.
[|Human|] What is the derivative of the function y = cos(x)?
[|AI|] The derivative of the function `y = cos(x)` is `y' = -sin(x)`. This means that the slope of the tangent line to the function `y = cos(x)` at any point `x` is given by the value of `-sin(x)` at that point.
[|Human|] 
What is the derivative of the function y = cos(x)?