Chapter 03

INTEGRALS

If derivatives break a function down to its instantaneous speed, Integrals build those moments back up to find the Total Accumulation.

Concept Zero: The Resolution of Infinity
The Area Problem
Simulation Data
Rectangles (n)
4
Est. Area
19.950
Exact Area
16.800
Error Margin
3.150

Pixels to Smoothness

Finding the area of a square is easy. Finding the area under a curve is hard. Our solution? Chop the curve into rectangles.

As you increase the Resolution (n), the rectangles get thinner. The blocky gaps disappear, and the estimated area becomes the exact area.

This visual-first method of slicing and summing is the heart of integration.

Notation Decoder

The Integral Sign

An elongated "S" standing for "Sum". It tells you to add up an infinite number of tiny slices.

f(x)
The Integrand

The function you are integrating. In geometry, this represents the height of the rectangles.

dx
The Differential

The infinitesimally small width of the rectangles. It marks the variable you are integrating with respect to.