Question 438860
  <pre><font face = "Tohoma" size = 4 color = "indigo"><b> 
Hi, 
a. 8, 11, 14, 17, 20, ... 
Arithmetic d = 3 {{{a[n]=a[1]+(n-1)*d}}} {{{a[100]=8+(99)*3}}}

b. 1, 16, 81, 256, 625, ...
   Neither {{{a[n]=n^4}}} {{{a[100] = 100^4}}}

c. 5, 15, 45, 135, 405, ...
  Neither  {{{a[n]= 5 * 3^(n-1)}}} {{{a[100]= 5* 3^(99)}}}

d. 2, 7, 12, 17, 22, ...
Arithmetic d = 5 {{{a[n]=a[1]+(n-1)*d}}} {{{a[100]=2+(99)*5}}}

e.1, 1/2, 1/4, 1/8, 1/16, ... 
Geometric r = 1/2 {{{a[n] = a[1]*r^(n-1)}}} {{{a[100] = 1*(.5)^(99)}}}