Give the next three terms and describe the rule IN WORDS for

Give the next three terms and describe the rule IN WORDS for the sequence 1, 1, 2, 3, 5, 8, 13, 21,...

Solution

The sequence given is 1, 1, 2, 3, 5, 8, 13, 21,.... The 3rd term onwards, each term is the sum of the previous 2 terms.In oter words, we have a_n+2 = a_n+1 + an . The three terms after 21, in the given sequence will be 21+13 = 34, 34 + 21 = 55 and 55 + 34 = 89.