University STEM, rebuilt
Lecture notes that behave like a good recitation, not a scanned PDF.
PolyStackLab is for students who already sat in lecture and still cannot see the argument. Start any open lesson without an account. Sign in when you want the lab and the video. Pay only when you need the full worked course.
Public notes first
Read the setup, definitions, and the first worked example with no login. If the page is not useful, you never create an account.
Labs and video with a free account
Interactive figures and teaching videos stay behind sign-in so the expensive parts of the course are not scraped as anonymous traffic.
Pro only when you need everything
Upgrade unlocks remaining derivations and problem sets. You are not asked to subscribe before you have seen whether the teaching works.
Subjects
Pick a course. Only published classes are open; the rest stay listed so you can see the map.
Calculus III
Multivariable Differentiation
Parametric curves, partial derivatives, and the geometry of functions of several variables.
Linear Algebra
Vector spaces & matrices
The language of modern STEM: bases, linear maps, and eigenvalues.
Differential Equations
Models that change in time
First-order systems, linear operators, and qualitative portraits.
University Physics
Mechanics
Motion, energy, and the conservative fields that show up again in vector calculus.
How access works
1. Guest
Open published lessons and read the public sections. No account, no paywall on the preview.
2. Free account
Unlock interactives and teaching videos. You will be asked to sign in the first time a lab or lecture appears.
3. Pro
Unlock the rest of each lesson: full derivations, identities, and the exercise set.