Patterns, sequences, and series

Sequences are functions on the positive integers. Students write explicit and recursive forms for arithmetic and geometric sequences, find any term from two given terms, and sum a short arithmetic series.

Specification · for a parent or teacher
Part no.
arithmetic-geometric-sequences
Course
High School Math 1 · Unit 13
Realm
Change
Difficulty
3 of 4 Grade 6–7 core. Multi-step, first symbolic work.
Qty
5 items

Part no. is the node's id; the realm is the kind of math; qty is how many practice items it carries.

Students can

classify arithmetic vs geometric; write explicit and recursive forms; find any term from two given terms; write a sequence as a function on Z+\mathbb{Z}^+; sum a short arithmetic series.

Ready when

12th term of an arithmetic and of a geometric sequence, from two given terms.

Formulas

Arithmetic
an=a1+(n1)da_n = a_1 + (n-1)d
Geometric
gn=g1rn1g_n = g_1 r^{n-1}
Sum of first n integers
i=1ni=n(n+1)2\sum_{i=1}^{n} i = \frac{n(n+1)}{2}

Watch for

an=a1+nda_n=a_1+nd; geometric with r<0r<0 skipped.

Before · requires

After · used by

— none

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arithmetic-geometric-sequences

Items: arithmetic-geometric-sequences-01 · arithmetic-geometric-sequences-02 · arithmetic-geometric-sequences-03 · arithmetic-geometric-sequences-04 · arithmetic-geometric-sequences-05