Question

2.

Consider the sequence {1,22,43,64,85,…}. Find n if an = 2332. Show all steps including the formulas used to calculate your answer.

Answer 1

n = 112

Explanation:

an = a1 + (n - 1)*d

d = 43 - 22 = 21 Try another one to confirm

d = 85 - 64 = 21

d = 21 So we have an arithmetic sequence.

a1 = 1

an = 2332

2332 = 1 + (n - 1)*21 Subtract 1 from both sides

2332 - 1 = (n - 1)*21

2331 = (n - 1)*21 Divide by 21

2331/21 = n - 1

111 = n - 1 Add 1 to both sides

112 = n