From 2b2446d0c3508450c3a6f13222b981573d5cfa43 Mon Sep 17 00:00:00 2001 From: shoko Date: Fri, 20 Mar 2026 02:51:10 +0000 Subject: [PATCH] Add study log for 2026-03-19: Khan Academy Sets Co-authored-by: han --- study-log.md | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/study-log.md b/study-log.md index 20aa18f..1783290 100644 --- a/study-log.md +++ b/study-log.md @@ -20,3 +20,17 @@ Questions: --- **Log** (newest first) + +**2026-03-19** +- Khan Academy: Sets & Their Representations (110 minutes) — https://www.khanacademy.org/math/ka-math-class-11/x0419e5b3b578592a:sets-ncert-new/x0419e5b3b578592a:sets-and-their-representations/v/what-are-sets + +Notes: +- Roster form: lists all elements explicitly, e.g. {1, 2, 3, ...} +- Set-builder form: describes elements by a rule, e.g. {x: x is an odd number less than 10} +- Sets can be empty, finite, or infinite + +Questions: +- Still unclear on terminology: positive integer, real number, integral number, etc. — these are number classification names, not strictly a set concept. Looking for a reference to solidify these. + +Comment: +- Notes are solid. The number classification question is actually about "number systems" — you'll encounter these more in the lecture notes when they talk about fields and groups. For now, just know that N = natural numbers, Z = integers, R = real numbers. Shortcut: look up "number sets notation" on Khan Academy or Wikipedia. Don't spend too long here — it'll click once you see them used in context.