What is arithmetic and geometric sequences?

Answer 1

an arithmetic sequence is a sequence where a number is constantly added to the previous number.
for example 1,2,3,4,5,6,7,8,9.... is an arithmetic sequence as the value of '1' is being added each time.

A geometric sequence is a sequence where there is a common multiple each time.
e.g. 1,2,4,8,16,32,64,128....is geometric as the common multiple is 2.

note that in both arithmetic and geometric sequences that ratio of additon of multiple does not change throughout the sequence.