←All concepts
Concept · Functions & Sequences
Summation techniques
grouping/pairing alternating signs, splitting into arithmetic+geometric parts, periodic (sine-defined) sequences
Practice this concept→
A Functions & Sequences set, untimed
Nothing named here yet.
No misconceptions are logged for this concept, so there is nothing named to trip you up. Practice it, and anything that does catch you will be added.
Key formulas
7- Arithmetic nth terman = a1 + (n − 1)d
- Arithmetic sumSn = n(a1 + an)/2 = n·a1 + n(n−1)d/2 (quadratic in n)
- Geometric nth terman = a1·rn−1
- Geometric sum (r ≠ 1): Sn = a1(1 − rn)/(1 − r)
- Geometric mean of a,bG = ±√ab
- Term from partial suman = Sn − Sn−1 for n ≥ 2, a1 = S1
- Geometric-series partial-sum form Sn = A·rn + C requires A + C = 0
Shaky underneath?
If the concept underneath still feels loose, patch it here before coming back to CSCA questions.
FoundationsPrecalculus bridgeAlgebra 2 foundations