Question

A group of students is arranging squares into layers to create a project. The first layer has 4 squares. The second layer has 8 squares. Which formula represents an arithmetic explicit formula to determine the number of squares in each layer?

a1 = 4; an = 4 ⋅ an − 1, n > 0

a1 = 4; an = 4 ⋅ an + 1, n > 0

a1 = 4; an = 4 + an + 1, n > 0

a1 = 4; an = 4 + an − 1, n > 0

Answer 1

D-a1 = 4; an = 4 + an − 1, n > 0

Explanation:

Thank me later

Answer 2

`a_1=4, \ a_n=4+a_(n-1),\ n>0`

Explanation:

A group of students is arranging squares into layers to create a project.

• The first layer has 4 squares.
• The second layer has 8 squares.
• The third layer has 12 squares.
• And so on

You can see that each next layer has 4 more squares than previous one. Hence, for n>0

`a_1=4, \\ \\a_2=8=4+a_1,\\ \\a_3=12=4+a_2,\\ \\...\\ \\a_n=4+a_(n-1)`