Find an explicit formula for the arithmetic sequence 12, 5, -2, -9,...12,5,−2,−9,...12, comma, 5, comma, minus, 2, comma, minus, 9, comma, point, point, point Note: the first term should be \textit{a(1)}a(1)start text, a, left parenthesis, 1, right parenthesis, end text. A(n)=

A(n) = 19 - 7n

Step-by-step explanation:

12, 5, -2, -9,...

First term, a = 12

Common difference, d = a2 - a1

a2 = 5

a1 = 12

Common difference, d = a2 - a1

= 5 - 12

= -7

d = -7

A(n) = a + (n - 1)d

A(n) = 12 + (n - 1) -7

= 12 + (-7n + 7)

= 12 - 7n + 7

= 12 + 7 - 7n

= 19 - 7n

A(n) = 19 - 7n

12-7(n-1)

Step-by-step explanation:

the radius is 2 times the diameter.

step-by-step explanation: