Math 2.0

definition

Derivative function

Definition

Let II be an open interval and let f ⁣:I→Rf \colon I \to \mathbb{R} be differentiable on II. The derivative function of ff is the function f′ ⁣:I→Rf' \colon I \to \mathbb{R} that maps each x∈Ix \in I to the derivative f′(x)f'(x) of ff at xx.

Remarks

Other notations are dfdx\frac{df}{dx} and DfD f. For example, the derivative function of x3x^3 is 3x23 x^2. The derivative function need not be continuous. See x^2 sin(1/x). Mathlib defines deriv f on all of R\mathbb{R}, with value 00 at points where ff is not differentiable.

Explanations

L1 human

The derivative function collects the slopes of ff at all points into one new function. We can then differentiate it again.

What this node needs for W1
  • an inventory row: the row of the inventory that the node accounts for (0 of 1)

The writing levels say how complete the text of a node is. They do not measure its truth.

What this needs

To read this node, read these 5 nodes in this order. The foundations come first, and the list ends with this node.

Each node uses the nodes above it. The colour of the bar on a box shows the evidence level, and the box also gives it as text. The list below has the same nodes.
  • no evidence level
  1. Limit point of a set definition
  2. Limit of a function definition
  3. Derivative definition
  4. Differentiable function definition
  5. Derivative function definition

What depends on this

58 nodes use this node, directly or through other nodes.

Sources

  1. Web https://en.wikipedia.org/wiki/Derivative, Definition