Math Problem Statement

Apply Gauss forward formula to obtain the value of f(x) at x = 3.5 from the tabler

X

2

3

4

5

f(x)

3.818

2.423

-1.027

-2.794

Solution

To apply the Gauss forward formula for interpolation, we need to estimate the value of f(x)f(x) at x=3.5x = 3.5 using the given table of values. Here’s the step-by-step application of the Gauss forward formula.

Step 1: Set up the data

Given the table:

\hline x & f(x) \\ \hline 2 & 3.818 \\ 3 & 2.423 \\ 4 & -1.027 \\ 5 & -2.794 \\ \hline \end{array}$$ ### Step 2: Calculate forward differences Compute the forward differences $$\Delta f$$ up to the third order: $$\Delta f(x) = f(x+1) - f(x)$$ Let’s calculate each forward difference: $$\begin{array}{c|cccc} x & f(x) & \Delta f & \Delta^2 f & \Delta^3 f \\ \hline 2 & 3.818 & -1.395 & -2.055 & -0.712 \\ 3 & 2.423 & -3.450 & -2.767 & \\ 4 & -1.027 & -1.767 & & \\ 5 & -2.794 & & & \\ \end{array}$$ ### Step 3: Gauss forward formula The Gauss forward formula is given by: $$f(x) = f_0 + p \Delta f_0 + \frac{p(p-1)}{2!} \Delta^2 f_0 + \frac{p(p-1)(p-2)}{3!} \Delta^3 f_0 + \ldots$$ where: - $$f_0 = f(3) = 2.423$$ (taking the nearest point as the reference) - $$p = \frac{x - x_0}{h} = \frac{3.5 - 3}{1} = 0.5$$ Now substitute the values: $$f(3.5) = 2.423 + (0.5)(-3.450) + \frac{(0.5)(-0.5)}{2}(-2.767) + \frac{(0.5)(-0.5)(-1.5)}{6}(-0.712)$$ Calculating each term: $$f(3.5) = 2.423 - 1.725 + 0.346 - 0.089$$ $$f(3.5) \approx 0.955$$ ### Final Answer The interpolated value of $$f(3.5)$$ using the Gauss forward formula is approximately: $$\boxed{0.955}$$ Would you like to go into details or have any questions? Here are some related questions: 1. How is Gauss backward formula different from Gauss forward formula? 2. Can you apply Newton's forward interpolation method to this data? 3. What are the limitations of using interpolation formulas? 4. How would the result differ if using Lagrange interpolation? 5. How to calculate higher order differences in interpolation? **Tip:** For more accurate results, ensure the data points are evenly spaced before applying interpolation formulas.

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Math Problem Analysis

Mathematical Concepts

Interpolation
Gauss Forward Formula
Finite Differences

Formulas

Gauss forward formula: f(x) = f0 + pΔf0 + (p(p−1)/2!)Δ^2f0 + (p(p−1)(p−2)/3!)Δ^3f0
Forward difference: Δf(x) = f(x+1) − f(x)

Theorems

Interpolation Theorem
Finite Difference Theorem

Suitable Grade Level

Grades 11-12