问题


There is a single choice question about high school mathematics. Answer the question by replying A, B, C or D.
Question: What is the 5th term in a series in which the first term is 2 and each subsequent term is −2 multiplied by the preceding term?
A. −16
B. 32
C. −32
D. 64
Answer:

答案

模型 模型答案 正确答案
金声玉亮2.0

B. 32
B
deepseekr1

The sequence starts with the first term as 2. Each subsequent term is obtained by multiplying the previous term by -2. Calculating step-by-step:

1. **Term 1**: 2
2. **Term 2**: \(2 \times (-2) = -4\)
3. **Term 3**: \(-4 \times (-2) = 8\)
4. **Term 4**: \(8 \times (-2) = -16\)
5. **Term 5**: \(-16 \times (-2) = 32\)

The fifth term is **32**, corresponding to option **B**.

Answer: B
B
gpto1 B B
GPT-4o To find the 5th term in the series where the first term is 2 and each subsequent term is −2 multiplied by the preceding term, we can follow these steps:

1. The first term (a1) is 2.
2. The second term (a2) is −2 * 2 = −4.
3. The third term (a3) is −2 * (−4) = 8.
4. The fourth term (a4) is −2 * 8 = −16.
5. The fifth term (a5) is −2 * (−16) = 32.

So, the 5th term is 32.

Answer: B
B
llama3.1-70B-Instruct

A
B
llama3.1-405B-Instruct

B. To solve, first determine the pattern in the series. The first term is 2, and each subsequent term is −2 multiplied by the preceding term. The series would look like this: 2, −4, 8, −16, 32. Therefore, the 5th term is 32.
B
DeepSeek-Coder-V2 C. −32 B
Qwen2-72B-Instruct C. −32 B
baichuan4 A. −16 B
doubao The first term is 2. The second term is 2 × (-2) = -4. The third term is -4 × (-2) = 8. The fourth term is 8 × (-2) = -16. The fifth term is -16 × (-2) = 32. So the answer is B. B
minimax Let's find the terms of the series step by step:

1st term: a_1 = 2
2nd term: a_2 = -2 * a_1 = -2 * 2 = -4
3rd term: a_3 = -2 * a_2 = -2 * (-4) = 8
4th term: a_4 = -2 * a_3 = -2 * 8 = -16
5th term: a_5 = -2 * a_4 = -2 * (-16) = 32

The 5th term in the series is 32.

Answer: B. 32
B
kimi A

The series starts with the first term being 2. Each subsequent term is obtained by multiplying the previous term by -2. So the series goes as follows:

1st term: 2
2nd term: 2 * (-2) = -4
3rd term: -4 * (-2) = 8
4th term: 8 * (-2) = -16
5th term: -16 * (-2) = 32

Therefore, the 5th term is 32, which corresponds to option B.
B
wenxinyiyan C

Explanation:
This is a geometric series where the first term is 2 and the common ratio is -2. The general formula for the nth term of a geometric series is $a_n = a_1 \times r^{(n-1)}$ where $a_n$ is the nth term, $a_1$ is the first term, r is the common ratio and n is the term number.

Using this formula, we can find the 5th term:

$a_5 = 2 \times (-2)^{(5-1)}$
$a_5 = 2 \times (-2)^4$
$a_5 = 2 \times 16$
$a_5 = 32 \times -1$ (because the -2 is raised to an even power, it becomes positive, but we multiply by an additional -2 outside the exponentiation)
$a_5 = -32$
B
zhipu To find the 5th term in the series where the first term is 2 and each subsequent term is −2 multiplied by the preceding term, we can follow these steps:

1. The first term (a₁) is 2.
2. The second term (a₂) is \( -2 \times a₁ = -2 \times 2 = -4 \).
3. The third term (a₃) is \( -2 \times a₂ = -2 \times -4 = 8 \).
4. The fourth term (a₄) is \( -2 \times a₃ = -2 \times 8 = -16 \).
5. The fifth term (a₅) is \( -2 \times a₄ = -2 \times -16 = 32 \).

So, the 5th term in the series is 32.

Therefore, the correct answer is:
B. 32
B
gpto1 B B
deepseekv3 To find the 5th term in the series, let's calculate each term step by step:

1. **First term (a₁):**
Given as 2.
\( a₁ = 2 \)

2. **Second term (a₂):**
Each subsequent term is \(-2\) multiplied by the preceding term.
\( a₂ = -2 \times a₁ = -2 \times 2 = -4 \)

3. **Third term (a₃):**
\( a₃ = -2 \times a₂ = -2 \times (-4) = 8 \)

4. **Fourth term (a₄):**
\( a₄ = -2 \times a₃ = -2 \times 8 = -16 \)

5. **Fifth term (a₅):**
\( a₅ = -2 \times a₄ = -2 \times (-16) = 32 \)

Thus, the 5th term is **32**.

Answer: **B**
B