Math Problem Statement

Estimate the value of tan(0.34π) using the linearization of f(x) = tan(πx) at the nearby point x = 1/3.

Solution

Let's go through the solution step-by-step based on the provided information.

Step-by-Step Solution

  1. Problem Overview: We are given the function f(x)=tan(πx)f(x) = \tan(\pi x) and need to estimate the value of tan(0.34π)\tan(0.34 \pi) using the linear approximation at a nearby point x=13x = \frac{1}{3}.

  2. Step A: Compute the Derivative of f(x)=tan(πx)f(x) = \tan(\pi x) at x=13x = \frac{1}{3}

    To find f(x)f'(x), we differentiate f(x)=tan(πx)f(x) = \tan(\pi x): f(x)=ddx(tan(πx))=πsec2(πx)f'(x) = \frac{d}{dx} \left( \tan(\pi x) \right) = \pi \sec^2(\pi x)

    Now, substitute x=13x = \frac{1}{3}: f(13)=πsec2(π3)f'\left(\frac{1}{3}\right) = \pi \sec^2\left(\frac{\pi}{3}\right)

    We know that sec(π3)=2\sec\left(\frac{\pi}{3}\right) = 2, so: f(13)=π22=4πf'\left(\frac{1}{3}\right) = \pi \cdot 2^2 = 4\pi

    Thus, the answer for part (a) is: f(13)=4πf'\left(\frac{1}{3}\right) = 4\pi

  3. Step B: Write Down the Linearization L(x)L(x) of tan(πx)\tan(\pi x) at x=13x = \frac{1}{3}

    The linearization L(x)L(x) of f(x)f(x) at x=13x = \frac{1}{3} is given by: L(x)=f(13)+f(13)(x13)L(x) = f\left(\frac{1}{3}\right) + f'\left(\frac{1}{3}\right) \cdot \left(x - \frac{1}{3}\right)

    We need to find f(13)f\left(\frac{1}{3}\right): f(13)=tan(π3)=3f\left(\frac{1}{3}\right) = \tan\left(\frac{\pi}{3}\right) = \sqrt{3}

    Now, substitute f(13)=3f\left(\frac{1}{3}\right) = \sqrt{3} and f(13)=4πf'\left(\frac{1}{3}\right) = 4\pi into the linearization formula: L(x)=3+4π(x13)L(x) = \sqrt{3} + 4\pi \left(x - \frac{1}{3}\right)

    Therefore, the answer for part (b) is: L(x)=3+4π(x13)L(x) = \sqrt{3} + 4\pi \left(x - \frac{1}{3}\right)

  4. Step C: Estimate tan(0.34π)\tan(0.34 \pi) Using Linear Approximation

    Since 0.340.34 is close to 130.3333\frac{1}{3} \approx 0.3333, we can use L(x)L(x) to estimate tan(0.34π)\tan(0.34 \pi) by setting x=0.34x = 0.34: L(0.34)=3+4π(0.3413)L(0.34) = \sqrt{3} + 4\pi \left(0.34 - \frac{1}{3}\right)

    Calculate 0.34130.34 - \frac{1}{3}: 0.3413=0.340.33330.00670.34 - \frac{1}{3} = 0.34 - 0.3333 \approx 0.0067

    Now, substitute back: L(0.34)3+4π0.0067L(0.34) \approx \sqrt{3} + 4\pi \cdot 0.0067

    Since π3.14159\pi \approx 3.14159: 4π0.006743.141590.00670.0844\pi \cdot 0.0067 \approx 4 \cdot 3.14159 \cdot 0.0067 \approx 0.084

    Thus: L(0.34)3+0.084L(0.34) \approx \sqrt{3} + 0.084

    Using 31.73205\sqrt{3} \approx 1.73205: L(0.34)1.73205+0.084=1.81605L(0.34) \approx 1.73205 + 0.084 = 1.81605

    Rounded to six decimal places, the estimate is: tan(0.34π)1.816050\tan(0.34 \pi) \approx 1.816050

Let me know if you'd like further details on any of these steps, or if you have any questions!


Here are some related questions you might explore:

  1. How does the linear approximation work for values farther from x=1/3x = 1/3?
  2. Why do we use the derivative in the linearization process?
  3. How does the error in approximation change as we move farther from x=1/3x = 1/3?
  4. Can we improve this approximation by using higher-order terms (Taylor series)?
  5. How would the approximation change if we estimated tan(0.35π)\tan(0.35\pi) instead of tan(0.34π)\tan(0.34\pi)?

Tip: When estimating trigonometric values, using nearby known values and linearization can be a powerful tool for quick approximations.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Differentiation
Linear Approximation
Trigonometric Functions

Formulas

f(x) = tan(πx)
f'(x) = π sec^2(πx)
L(x) = f(x_0) + f'(x_0)(x - x_0)

Theorems

Linearization
Derivative of Tangent Function

Suitable Grade Level

Grades 11-12