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.
An arithmetic sequence is when you are adding a constant term to get the the next value in the sequence. A geometric sequence is when you multiply by a constant term to get the next value in the sequence. Therefore #1 is geometric since the next term is obtained by multiplying the previous term by -2 and #2 is arithmetic since the next term is obtained by adding -20 to the previous term. a a Â· 3 years ago. Thumbs up. 0.