Math Problem Statement

Use differentials to estimate the value of 4th root of 16.3. Compare the answer to the value of the 4th root of 16.3 found using a calculator.

Solution

The task is to estimate the value of 16.34\sqrt[4]{16.3} using differentials and compare it to the actual value calculated by a calculator. Here's a step-by-step breakdown to solve it using differentials:

Step 1: Approximation Using Differentials

We can estimate the value of 16.34\sqrt[4]{16.3} by using the function: f(x)=x4f(x) = \sqrt[4]{x} This function can be approximated by using its tangent line near a value where we already know the result. Let's choose x=16x = 16, since 164=2\sqrt[4]{16} = 2.

The differential approximation formula is: f(x+Δx)f(x)+f(x)Δxf(x + \Delta x) \approx f(x) + f'(x) \cdot \Delta x Where Δx=16.316=0.3\Delta x = 16.3 - 16 = 0.3.

Step 2: Compute the Derivative

The derivative of f(x)=x4f(x) = \sqrt[4]{x} is: f(x)=14x34=14x34f'(x) = \frac{1}{4}x^{-\frac{3}{4}} = \frac{1}{4\sqrt[4]{x^3}} At x=16x = 16: f(16)=141634=148=132f'(16) = \frac{1}{4 \cdot \sqrt[4]{16^3}} = \frac{1}{4 \cdot 8} = \frac{1}{32}

Step 3: Estimate the Value

Now we can estimate f(16.3)f(16.3) using the differential approximation: f(16.3)f(16)+f(16)(16.316)f(16.3) \approx f(16) + f'(16) \cdot (16.3 - 16) f(16.3)2+1320.3=2+0.009375=2.009375f(16.3) \approx 2 + \frac{1}{32} \cdot 0.3 = 2 + 0.009375 = 2.009375

Step 4: Compare with the Actual Value

Using a calculator, we find the actual value of 16.34\sqrt[4]{16.3}.

16.342.00926\sqrt[4]{16.3} \approx 2.00926

Step 5: Comparison

The estimated value using differentials is 2.0093752.009375, while the actual value from the calculator is 2.009262.00926. The differential method gives a very close approximation to the actual value.


Would you like more details on any part of the process?

Here are some related questions:

  1. How do differentials help in estimating functions?
  2. Can the same approach be applied to other roots or powers?
  3. What role does the choice of xx (in this case, 16) play in the accuracy of the approximation?
  4. How does the error in this approximation compare with larger values of Δx\Delta x?
  5. What other methods can be used to estimate the value of roots without a calculator?

Tip: When using differentials for approximation, choose a base value of xx for which you know the exact result, to minimize the error in estimation.

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Math Problem Analysis

Mathematical Concepts

Differentiation
Approximation using differentials
Roots and radicals

Formulas

Differential approximation: f(x + Δx) ≈ f(x) + f'(x) ⋅ Δx
Derivative of 4th root: f'(x) = 1/4 * x^(-3/4)
4th root formula: x^(1/4)

Theorems

Differential Approximation Theorem

Suitable Grade Level

High School - Calculus