geometric progression
noun [ C or U ] mathematics specialized uk/ˌdʒiː.əˈmet.rɪk prəˈɡreʃ.ən/ us/ˌdʒiː.əˈmet.rɪk prəˈɡreʃ.ən/ (also geometric sequence, /ˌdʒiː.əˈmet.rɪk ˈsiː.kwəns/ /ˌdʒiː.əˈmet.rɪk ˈsiː.kwəns/); (also old-fashioned geometrical progression, uk/ˌdʒiː.əˈmet.rɪ.kəl prəˈɡreʃ.ən/ us/ˌdʒiː.əˈmet.rɪ.kəl prəˈɡreʃ.ən/)
几何级数：从第一项开始，以后毎一项都是它前一项乘上一个固定数，如2, 6, 18, 54...
an ordered set of numbers, where each number in turn is multiplied by a particular amount to produce the next, for example 2, 6, 18, 54 ...
Epidemics are an example of geometric progression: when a virus spreads through a population, it doubles and doubles again. 流行病是几何级数的一个例子：病毒在人群中传播时，会成倍成倍地感染。
The terms 1,2,4,8 form a geometric sequence. 1,2,4,8四个项构成一个几何序列。
Compare: arithmetic progression
- More examples
- In this view memes spread among consumers in a geometric progression.
- This chain model is based on the hope of financial gain resulting from a geometric progression of the number of people recruited.
- In a warm climate, bees flourish to such an extent that hives proliferate in geometric progression.
- The essence of his view was that a country's population had a tendency to grow in geometric progression over time.
- The population on the limited surface of this planet which bears us, is increasing in almost geometrical progression.