Explicit formulas Write the first four terms of the sequence {an}n=1 infinity. 9. an=1/10n 11. an = 1 + sin(pin/2) Recurrence re
lations Write the first four terms of the sequence {an} defined by the following recurrence relations. Enumerated sequences Several terms of a sequence {an}n=1 infinity are given. Find the next two terms of the sequence. Find a recurrence relation that generates the sequence (supply the initial value of the index and the first term of the sequence). Find an explicit formula for the general nth term of the sequence. 17. {1. 1/2, 1/4, 1/8, 1/16,....} 19. {1,2,4,8,16,...} 21. {1.3,9,27,81,...}