https://www.bettermath.org/articles/ Articles on IB Mathematics AA HL by Hasan K.en https://www.bettermath.org/articles/opposite-of-a-derivative/https://www.bettermath.org/articles/opposite-of-a-derivative/ Mon, 05 Oct 2026 00:00:00 +0000Subtraction undoes addition and division undoes multiplication. Differentiation has an opposite too, and the Fundamental Theorem of Calculus says that this opposite is how we find areas. https://www.bettermath.org/articles/what-a-proof-is/https://www.bettermath.org/articles/what-a-proof-is/ Sat, 03 Oct 2026 00:00:00 +0000Five cases can agree and the sixth can fail. What a mathematical proof is, how mathematical induction proves a statement for every whole number from just two facts, and the mistakes that break an induction proof. https://www.bettermath.org/articles/adding-infinitely-many-numbers/https://www.bettermath.org/articles/adding-infinitely-many-numbers/ Tue, 29 Sep 2026 00:00:00 +0000How can a sum that never ends have a finite answer? The formula for an infinite geometric series, and why it is true. https://www.bettermath.org/articles/fundamental-theorem-of-calculus/https://www.bettermath.org/articles/fundamental-theorem-of-calculus/ Tue, 29 Sep 2026 00:00:00 +0000Adding up thin rectangles and undoing a derivative look like different problems. The Fundamental Theorem of Calculus says they give the same answer, and the proof fits on one page. https://www.bettermath.org/articles/how-to-study-with-bettermath/https://www.bettermath.org/articles/how-to-study-with-bettermath/ Mon, 28 Sep 2026 00:00:00 +0000The notes are long for a reason. A short guide to reading a chapter, using Your Turn, and turning mistakes into progress.