← All units AP Calculus BC · Unit 9
Parametric · Polar · Vectors

Paths, curves &
spirals, made visual.

A fly's path through a room, a planet's orbit, a spiral, a rose — some curves can't be written as a single function of x. This unit gives you three new languages for motion and shape: parametric, vector, and polar.

9
CED topics · 9.1–9.9
4
Interactive tools
~12%
of the BC exam
Explore the unit
The toolkit

Four ways into the unit

Put it to the test

The capstone

Exam Practice

Mixed AP-style questions & full FRQs

Multiple-choice with deep explanations and a weak-spot tracker, plus full 9-point free-response — the parametric/vector motion problem and the polar-area problem, the two question types Unit 9 always brings to the exam.

Start practicing
Cheat Sheet — every formula and the "which setup?" logic, on one printable page
Where to start

Two ways through

Learning it for the first time

Go in order. Parametric sets up the idea of a parameter driving a curve; Vectors is the same idea in motion language; then Polar graphing and Polar area build the other coordinate system from the ground up. Each tool animates the thing the textbook only describes.

Reviewing before a test

Drill the two things that lose points: the parametric motion problem (displacement vs. distance) and polar area (½∫r², and finding the right limits). The cheat sheet has every formula and the "which setup?" logic on one printable page.