How deeply does D3.js in Action, Third Edition cover cosine function?

Defines the right-triangle ratio and works through coordinate equations, without developing broader trigonometric theory.

Cosine function

As explained in D3.js in Action, Third Edition

Cosine is a trigonometric function that gives the ratio of the adjacent side to the hypotenuse in a right triangle.

The cosine function relates an angle in a right triangle to the adjacent side and hypotenuse. In a radial visualization, it converts an angle and radius into a vertical coordinate: y = radius × cos(θ). Because the SVG coordinate system points downward, the implementation multiplies the result by −1. section 14.5.1

Positioning month axes

A circle assigns each month an angle from 0 to nearly 2π. For every month, an SVG line starts at (0, 0), while its endpoint uses x = radius × sin(θ) and y = −radius × cos(θ). January begins at twelve o’clock, and the remaining axes spread around the circle. section 14.5.1

How D3.js in Action, Third Edition covers it

liveBook manning.com

Read D3.js in Action, Third Edition on liveBook Get the book at manning.com

Also explained in

liveBook manning.com

Math for Web Designcos() is a CSS mathematical function that returns the cosine of an angle.
liveBook manning.com

Julia as a Second Languagecos is a Julia function that computes the cosine of an angle or numeric value.

Compare how 3 books explain cosine function →

Related concepts

rotationused by · A rotation is a geometric transformation that turns points or objects about a fixed center, origin, or axis through an angle while preserving distances and angles.
positional embeddingused by · A positional embedding is a learned or fixed representation that encodes an element’s position or order in a sequence and is incorporated into its content representation.
trigonometrykind of · Trigonometry is the branch of mathematics studying relationships among angles, lengths, geometric ratios, coordinates, and periodic functions.
type-generic macroalternative to · A type-generic macro is a macro-based interface whose expansion selects or adapts operations according to the types of its arguments or associated objects.
operatorkind of · An operator is a symbol, keyword, or language construct that specifies an operation on one or more operands.
sine functionproduced by · The sine function is a periodic trigonometric function that maps a real number or angle to a value between −1 and 1.

This explainer was generated by Manning's knowledge graph from the text of D3.js in Action, Third Edition. The section links point to the parts of the book it draws on.