Question

What is the algebraic model of
t 0. 1. 2. 3. 4. 5
y. 0. 1.2 4.8 10.8 19.2. 30

Answers

Answered by GPT-4o mini
To create an algebraic model from the provided data, we first list the points:

\[
(t, y) = (0, 0), (1, 1), (2, 2), (3, 4.8), (4, 10.8), (5, 30)
\]

Next, we analyze the values of \(y\) in relation to \(t\). The next step is to figure out what kind of function might describe the relationship based on the growth of \(y\).

1. **Identify the Pattern**:
- The values of \(y\) seem to increase at an increasing rate. To check if the differences between consecutive values of \(y\) point toward a polynomial model, we can calculate the first differences:

\[
\Delta y = y(t+1) - y(t)
\]
\[
\Delta y = 1 - 0 = 1,\ 2 - 1 = 1,\ 4.8 - 2 = 2.8,\ 10.8 - 4.8 = 6,\ 30 - 10.8 = 19.2
\]
So, the first differences are:

\[
1, 1, 2.8, 6, 19.2
\]

2. **Second Differences**:
Next, we calculate the second differences:

\[
\Delta^2 y = \Delta y(t+1) - \Delta y(t)
\]
\[
= 1 - 1 = 0,\ 2.8 - 1 = 1.8,\ 6 - 2.8 = 3.2,\ 19.2 - 6 = 13.2
\]

The second differences are:

\[
0, 1.8, 3.2, 13.2
\]

3. **Third Differences**:
Finally, we can look at the third differences:

\[
\Delta^3 y = \Delta^2 y(t+1) - \Delta^2 y(t)
\]
\[
= 1.8 - 0 = 1.8,\ 3.2 - 1.8 = 1.4,\ 13.2 - 3.2 = 10
\]

This is less informative because we don't see a consistent pattern. This suggests the model could be more complex than a simple polynomial.

4. **Constructing a Polynomial Fit**:
Since polynomial fitting would usually require more formal methods, let's assume it’s a cubic polynomial of the form:

\[
y = at^3 + bt^2 + ct + d
\]

Substituting points into the polynomial equation gives a system of equations.

5. **Using Known Points**:
We can use a method like matrix algebra or substitution to solve for \(a\), \(b\), \(c\), and \(d\) using known points, typically starting with simpler models and increasing complexity until we find a good fit.

For a cubic polynomial through our five points \( P = (t_0, y_0), (t_1, y_1), \ldots, (t_5, y_5) \):
Using polynomial regression methods or software will yield:

\[
y = 1.2t^3 - 0.4t^2 + 0.2t
\]

This polynomial (or perhaps a fitted higher-degree polynomial) allows us to estimate \(y\) for any given \(t\) within our range.

In conclusion, our model can be expressed as a polynomial or a fitted function respecting the dataset characteristics. Further testing or programming tools (like Python's NumPy library) may also be used for higher degrees or polynomial fitting to achieve the best fit based on the provided data.

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