Sequences & Series
Section: AlgebraGRE frequency: Medium-HighPro
1. Core Idea
A sequence is an ordered list; a series is its sum. The GRE tests two families plus "spot the pattern":
- Arithmetic: you add a constant
deach step. - Geometric: you multiply by a constant
reach step.
The diagnostic: look at consecutive differences (constant -> arithmetic) and consecutive ratios (constant -> geometric).
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