Chapters
Graded once a chapter has 10 timed answers: papers, part tests, chapter tests and timed past-paper sets (a 15-question strength check, Grade it, among them). Recent answers count more: one 90 days old counts half. His whole record counts as 5 questions more, so an old weakness fades but is never dropped. The line gives the score, his last 60 days and his last test.1 of 4 chapters have a note · jump to
Sequence and Series
Mathematics · Weak 31% · Saved 3 Nov: First version, from the class module
1 · Formulas and when each holds
- AP: aₙ = a + (n − 1)d; Sₙ = n/2 (2a + (n − 1)d).
- GP: aₙ = arⁿ⁻¹; Sₙ = a(rⁿ − 1)/(r − 1), r ≠ 1; S∞ = a/(1 − r) when |r| < 1.
- AM ≥ GM ≥ HM for positive numbers, equal only when all are equal.
2 · Question types and the first step
- Terms given in a GP: write them as a/r, a, ar.
- Sum of a series with a pattern in the differences: find the general term first.
3 · Traps
S∞: only when |r| < 1; check before using it.
4 · My additions
- For three terms in AP, take a − d, a, a + d.
Parabola
Mathematics · Shaky 53%
No note yet.
Definite Integration
Mathematics · Weak 23%
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Inverse Trigonometric Functions
Mathematics · Shaky 54%
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