# If a[1]=4 and r=2, what are the first four terms of the geometric sequence?

##### 1 Answer

#### Explanation:

Recall that the geometric sequence formula is written as:

#color(blue)(|bar(ul(color(white)(a/a)t_n=ar^(n-1)color(white)(a/a)|)))#

where:

**Determining the First Four Terms**

#color(green)(|bar(ul(color(white)(a/a)t_1=4color(white)(a/a)|)))#

#color(red)(rArr)# Sequence thus far:#4,...#

#t_n=ar^(n-1)#

#t_2=4(2)^(2-1)#

#t_2=4(2)^1#

#color(green)(|bar(ul(color(white)(a/a)t_2=8color(white)(a/a)|)))#

#color(red)(rArr)# Sequence thus far:#4,8,...#

#t_n=ar^(n-1)#

#t_3=4(2)^(3-1)#

#t_3=4(2)^2#

#t_3=4(4)#

#color(green)(|bar(ul(color(white)(a/a)t_3=16color(white)(a/a)|)))#

#color(red)(rArr)# Sequence thus far:#4,8,16,...#

#t_n=ar^(n-1)#

#t_4=4(2)^(4-1)#

#t_4=4(2)^3#

#t_4=4(8)#

#color(green)(|bar(ul(color(white)(a/a)t_4=32color(white)(a/a)|)))#

#color(red)(rArr)# Sequence thus far:#4, 8, 16, 32#