Visual Math
Maths explained the way I needed to see it: with the graph next to the formula.
I wrote this as a manuscript in Romania in 2005–2006, while tutoring children aged 8 to 18. What started it was Mathcad — the first time I could see a graph appear on demand instead of drawing it by hand. I moved to MATLAB later, for the exports. Then the whole thing became one unmanageable pile of Word files and I stopped.
This site is that manuscript, brought back.
What is here
All 27 chapters, restored and translated, across three parts.
- Algebra — 16 chapters: functions, linear and quadratic, powers and radicals, logarithms, progressions, combinatorics, complex numbers, polynomials, vectors, linear algebra, geometric transformations
- Analysis — 8 chapters: sequences, limits, continuity and derivatives, antiderivatives, definite integrals and their applications, differential equations
- Geometry & Trigonometry — 3 chapters: analytic geometry, quadrilaterals, trigonometry
Press Ctrl+K to search the whole book. The index is built into the page and
runs in your browser, so nothing you type is sent anywhere.
Graphs you can move
Four chapters have a graph with sliders — change a coefficient and watch the curve answer:
The rebuilt graphs page holds 36 more, redrawn as vector artwork from the original 2005 MATLAB data — each one shown next to the Python that draws it, which was the idea behind the book in the first place: teach the plotting language beside the maths.
About the equations
Every formula here is the original 2006 typesetting. Just over half — 1,436 of 2,788 — have been decoded from their MathType source into live text, so you can select, copy and search them. The rest are re-rendered from the original at four times the display resolution: sharp at any zoom, but not selectable.
That split is a deliberate rule, not a stopping point. A decoder that is unsure produces maths that looks right and is wrong, which on a maths site is worse than a picture — so anything that cannot be proved correct stays a picture. The share of decoded text goes up as the decoder improves, and it has gone down once, when equations that had been shipping quietly truncated were withdrawn.
If you ever see a formula that looks nearly right, it is worth reporting. The short ones are the hardest to spot.
About the language
The manuscript was written in Romanian and has been translated in full, keeping the standard English terms rather than literal translations — quadratic function rather than function of the second degree.