Math Problem Statement

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

Solution

The question asks to apply the Gauss forward interpolation formula to find f(x)f(x) at x=3.5x = 3.5. Given the table, here's how we approach it.

Table of Values:

xxf(x)f(x)
1.58.963
2.524.364
3.566.340
4.5180.034

Gauss Forward Interpolation Formula:

The Gauss forward formula is a Newton forward difference interpolation formula, expressed as:

f(x)=f0+pΔf0+p(p1)2!Δ2f0+p(p1)(p2)3!Δ3f0+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 + \cdots

Where:

  • p=xx0hp = \frac{x - x_0}{h}
  • hh is the uniform spacing between the xx-values.
  • Δf0,Δ2f0,Δ3f0\Delta f_0, \Delta^2 f_0, \Delta^3 f_0 are the forward differences at x0x_0.

Step 1: Calculate pp

Given that we are to find f(x)f(x) at x=3.5x = 3.5 and the closest value in the table is x0=2.5x_0 = 2.5, the uniform step h=1.0h = 1.0 (since the spacing between consecutive xx-values is 1.0).

Now, we compute pp:

p=3.52.51=1p = \frac{3.5 - 2.5}{1} = 1

Step 2: Forward Differences

Next, we calculate the forward differences from the given data. Let me do the calculations for the forward differences and plug them into the formula to obtain the required result.Here are the calculated forward differences from the given dataHere are the calculated forward differences from the given

DifferencesValues
Δf0\Delta f_015.401
Δ2f0\Delta^2 f_026.575
Δ3f0\Delta^3 f_045.143

Step 3: Apply the Gauss Forward Formula

Using the forward differences and the formula:

f(x)=f0+pΔf0+p(p1)2!Δ2f0+p(p1)(p2)3!Δ3f0f(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

Since p=1p = 1, we have:

f(3.5)=24.364+115.401+1(11)2!26.575+1(11)(12)3!45.143f(3.5) = 24.364 + 1 \cdot 15.401 + \frac{1(1-1)}{2!} \cdot 26.575 + \frac{1(1-1)(1-2)}{3!} \cdot 45.143

The terms involving higher-order differences (Δ2f0\Delta^2 f_0 and Δ3f0\Delta^3 f_0) drop out because p(p1)=0p(p-1) = 0 for them.

Thus:

f(3.5)=24.364+15.401=39.765f(3.5) = 24.364 + 15.401 = 39.765

So, the value of f(3.5)f(3.5) is approximately 39.765 based on Gauss forward interpolation.

Would you like any further explanation or calculations?

Related Questions:

  1. How is the Gauss forward interpolation formula derived?
  2. Can the backward formula be used to obtain the same result?
  3. What would happen if the points were unevenly spaced?
  4. How do higher-order terms affect accuracy in interpolation?
  5. What is the difference between Newton's forward and backward formulas?

Tip: Interpolation accuracy depends on how well the given data fits the function being approximated, so including more data points may yield better results!

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Math Problem Analysis

Mathematical Concepts

Interpolation
Gauss Forward Interpolation
Finite Differences

Formulas

Gauss Forward Interpolation Formula: f(x) = f_0 + p Δf_0 + (p(p-1)/2!) Δ^2f_0 + (p(p-1)(p-2)/3!) Δ^3f_0
p = (x - x_0) / h

Theorems

Gauss Forward Interpolation Formula

Suitable Grade Level

Undergraduate