SL 01 Sequences and Series (Revision - GDC)

• I only

• II only

• I and III only

• II and III only

Let a_n be the nth term of an arithmetic sequence. If a₉ = -7 and a₁₃ = -19 , which of the following are true?

I. a₁ > 0

II. a₂₀ - a₁₉ > 0

III. a₁₀ ÷ a₂₀ > 0

• I and II only

• I and III only

• II and III only

• I, II and III

Let a_n be the nth term of an arithmetic sequence. If a₁₀ = 33 and a₁₅ = 18, which of the following is/are true?

I. The common difference is -3.

II. 63 is a term of the sequence.

III. The sequence has 21 non-negative terms.

• I only

• II only

• I and III only

• II and III only

The sum of the 2nd term and the 3th term of an arithmetic sequence is 20 while the sum of the 5th term and the 6th term of the sequence is 32. The first term of the sequence is

• 2.

• 7.

• -2.

• -7.

Let a, b and c be positive integers. If a + c = 2b, which of the following must be a geometric sequence/geometric sequences?

I. 7^a, 7^b, 7^c

II. 7^{a + 1}, 7^{b + 1}, 7^{c + 1}

III. a⁷, b⁷, c⁷

• I and II only

• I and III only

• II and III only

• I, II and III

Let a_n be the nth term of a geometric sequence. If a₂ = 576 and a₄ = 324, which of the following must be true?

I. a₈ ÷ a₉ > 1

II. a₅ ÷ a₇ > 1

III. a₁ > 0

• I only

• II only

• I and III only

• II and III only

If the 3rd and the 7th term of a geometric sequence are 3 and 48 respectively, which of the following must be true?

I. The 5th term is 12.

II. The sequence has no negative terms.

III. All the terms in the sequence are integers.

• I only

• II only

• I and III only

• II and III only

The sum of the 3rd term and the 4th term of a geometric sequence with positive terms is 576 while the sum of the 5th term and the 6th term of the sequence is 8. The common ratio of the sequence is

Let a_n be the nth term of a geometric sequence. It is given that a₆ - a₅ = 8 and a₇ - a₆ = 24. The common ratio is

• 2.

• 3.

The product of the 6th term and the 9th term of a geometric sequence is 3200 while the product of the 7th term and the 10th term of the sequence is 800. The common ratio of the sequence is

• 2 or -2.

• 4 or -4.

• 0.5 or -0.5.

• 0.25 or -0.25