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Calculus › Computing derivatives › second derivative

second derivative

Computing derivatives

The second derivative of a function measures the instantaneous rate of change of the first derivative, providing information about the concavity of the original function and whether the slope of the tangent line is increasing or decreasing. It is obtained by differentiating the first derivative of the function, and its units are determined by the units of the first derivative divided by the units of the independent variable.

Definition

The second derivative of a function is obtained by differentiating the first derivative of that function. It provides a measure of the rate at which the slope of the tangent line to the function changes, indicating whether the function is concave up or concave down at a given point. The sign of the second derivative determines the direction of the concavity, with a positive value indicating concave up and a negative value indicating concave down.

f′′(x)=limh0f(x+h)-f(x)h

Interpretation

The second derivative of a function provides the instantaneous rate of change of the first derivative, which itself represents the rate of change of the original function. This interpretation is crucial for understanding acceleration in motion or the rate of temperature change in dynamic systems.

Conditions and Properties

The sign of the second derivative indicates whether the slope of the tangent line to the function is increasing or decreasing, which is essential for understanding the behavior of the function.

Applications

For instance, in motion, the second derivative of position with respect to time represents acceleration, with units such as feet per minute per minute, reflecting the instantaneous rate of change of velocity.

Notes & references