Free public beta until December 4, 2026: every course is open, no card needed. After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept. How the beta works

linear transformation

A random variable rule of the form Y=aX+b -- a stretch (or flip) by a, followed by a slide by b, the only transformation this course solves in full closed form.

$Y=aX+b$ .