Question

Find the function of the arithmetic sequence with the folowing points
(0, 14), (1, 20), (2, 27)

Answers

GPT-4o mini
An arithmetic sequence can be represented as a linear function of the form \( f(x) = mx + b \), where \( m \) is the common difference and \( b \) is the first term when \( x = 0 \).

To find the function based on the given points, we can first find the common difference \( m \):

1. From \( (0, 14) \) to \( (1, 20) \):
\[
m = 20 - 14 = 6
\]

2. From \( (1, 20) \) to \( (2, 27) \):
\[
m = 27 - 20 = 7
\]

It seems there’s an inconsistency here with the differences calculated. To check, let’s look at the points and determine if the arithmetic sequence is consistently applied:

- From \( f(0) = 14 \) to \( f(1) = 20 \) is indeed \( 6 \).
- From \( f(1) = 20 \) to \( f(2) = 27 \) is \( 7 \).

This inconsistency means that these points aren't forming a perfect arithmetic sequence with a uniform difference. It looks like there’s a misunderstanding of the arithmetic sequence nature.

To find a quadratic polynomial that fits these points, we will instead assume \( f(x) = ax^2 + bx + c \). Since we have three points, we can set up a system of equations using them:

1. From the point \( (0, 14) \):
\[
c = 14
\]

2. From the point \( (1, 20) \):
\[
a(1)^2 + b(1) + c = 20 \quad \Rightarrow \quad a + b + 14 = 20 \quad \Rightarrow \quad a + b = 6
\]

3. From the point \( (2, 27) \):
\[
a(2)^2 + b(2) + c = 27 \quad \Rightarrow \quad 4a + 2b + 14 = 27 \quad \Rightarrow \quad 4a + 2b = 13 \quad \Rightarrow \quad 2a + b = 6.5
\]

Now we have a system of equations:
1. \( a + b = 6 \) (Equation 1)
2. \( 2a + b = 6.5 \) (Equation 2)

Now, we can eliminate \( b \) by subtracting Equation 1 from Equation 2:
\[
(2a + b) - (a + b) = 6.5 - 6
\]
\[
a = 0.5
\]

Now, substituting \( a \) back into Equation 1 to solve for \( b \):
\[
0.5 + b = 6 \quad \Rightarrow \quad b = 5.5
\]

Now, substituting \( a \) and \( b \) back to find \( c \):
\[
c = 14
\]

Thus, the function that describes the points given is:
\[
f(x) = 0.5x^2 + 5.5x + 14
\]

It's not an arithmetic function; it is actually a quadratic function, and this results from the points provided. Please refer to the data points for the sequence, as they may not correspond directly to linear functional relationships.

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