The Louvre Museum as seen through the Louvre Pyramid glass in Paris, France. From the National Geographic book The 10 Best of Everything. Smithsonian Institution, Washington, D.C. The Smithsonian is the worldâs largest research and museum complex, with 19 museums and galleries, the National Zoological Park, and various research stations.
1 An arithmetic sequence is a sequence with the difference between two consecutive terms constant. 2  The difference is called the common difference. 3  A geometric sequence is a sequence with the ratio between two consecutive terms constant. 4  This ratio is called the common ratio.
The following sequences are geometric sequences: Sequence A: 1 , 2 , 4 , 8 , 16 , ... Sequence B: 0.01 , 0.06 , 0.36 , 2.16 , 12.96 , ... Sequence C: 16 , -8 , 4 , -2 , 1 , ... For sequence A, if we multiply by 2 to the first number we will get the second number. This works for any pair of consecutive numbers. The second number times 2 is the third number: 2 Ã 2 = 4, and so on. For sequence B, if we multiply by 6 to the first number we will get the second number.