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Determine the explicit form of the arithmetic sequence given the following information.
a3 = 11 and a6 = 20

Respuesta :

jcherry99

Answer:

Step-by-step explanation:

a3 = 11

a6 = 20

11 = a1 + (n - 1)*d

11 = a1 + (3 - 1)*d

11 = a1 + 2*d

20 = a1 + (n - 1)*d

20 = a1 + (6-1)*d

20 = a1 + 5*d

11 = a1 + 2d                   Subtract to get rid of the a1

9 = 3d                           Divide by 3

9/3 = d

d = 3

11 = a1 + 2*3

11 = a1 + 6                     Subtract 6

11-6 = a1

a1 = 5

tn = 5 + (n - 1)^3

tn = 5 + 3n - 3

tn = 5 - 3 + 3n

tn = 2 + 3n

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