Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
A twice differentiable function is a function that has two continuous derivatives. This means that the function can be differentiated twice, and both of those derivatives are also continuous.
The first derivative test is used to determine whether critical points of a function correspond to local maxima or minima. It involves analyzing the sign changes of the first derivative around these points.
Hessian Matrix: The Hessian matrix is a square matrix of second-order partial derivatives of a multivariable function. It provides information about concavity and convexity at critical points.
Critical points are values in the domain of a function where either the first derivative is zero or does not exist. They can correspond to local extrema or inflection points on the graph of the function.