ARITHMETIC SEQUENCE, MEANS AND SERIES

Which of the following is the correct formula in finding the nth term of an arithmetic sequence?

• a_n = a₁ + (n - 1)d

• a_n = a₁ + (n + 1)d

• a_n = a₁ - (n + 1)d

• a_n = a₁ - (n - 1)d

What is the twelfth term in the sequence 3, -6, 12, . . . ?

• -2,048

• -6,144

• 6,144

• -531,441

For n = 1,2,3 . . .the arithmetic sequence given by the equation a_n = (-3)ⁿ + 4, will produce the terms of the sequence:

• {1, -2, -5, -8...}

• {1, -5, -23, -77. . .}

• {1, 13, -23, 85. . .}

• {1, 10,-5, 85. . .}

In an arithmetic sequence if a₁₅ =108 and d=7, find a₁.

• 10

• 101

• 14

• 206

What is the nth term of the given the sequence:

25, 21, 17, 13,...

• a_n = 4n + 29

• a_n = -4n + 25

• a_n = -4n + 29

• an = 4n + 25

Find the arithmetic mean between 12 and 30

• 20

• 21

• 22

• 23

What is the arithmetic mean between x and x+12

• x + 3

• x + 4

• x + 5

• x + 6

Find the sum of the first ten terms of the sequence 4, -12, 36, -108 . . . ?

• 59,050

• -78,732

• -59,048

• 118,096

What is the sum of the first 50 terms of the series 2 + 17 + 32 + 47 + ...?

• 18,475

• 19,125

• 18,235

• 1,600

Insert two arithmetic means between 50 and 62

• 58,60

• 52,54

• 54,58

• 56,58