How do I visualize derivatives? I know how to derive functions, but for some reason I need a visual to fully understand the concept.

1 Answer
Jun 21, 2018

See answer below

Explanation:

Given: How do I visualize derivatives?

Derivatives are slope functions. When you evaluate a derivative at any location along the original function, you get the slope at that location.

If the original function is a cubic (degree = 3), then it's first derivative is a quadratic (degree = 2) function. Wherever there was a relative maximum or relative minimum in the original function, the slope will be zero which means the first derivative's y-value at the maximum or minimum will be equal to zero.

This would be the degree of the derivatives is you have a cubic function as the original function:

1st derivative: quadratic
2nd derivative: linear function
3rd derivative: horizontal line
4th derivative: y = 0

Here's an example:
f(x) = x^3 + x^2 - 6x + 2 seen as pink on the graph

f'(x) = 3x^2 + 2x - 6 seen as purple on the graph.

f'(x) crosses the x-axis when f(x) is both at a relative maximum and a relative minimum.

f'(x) has a negative y-value when f(x) is decreasing and a positive y-value when f(x) is increasing.

![https://www.symbolab.com/graphing-calculator](useruploads.socratic.org)