Math Problem Statement

Find the value of thetaθ in the interval 0, is less than or equal to, theta, is less than or equal to, start fraction, pi, divided by, 2, end fraction0≤θ≤2π​ that corresponds to the point on the curve r, equals, minus, 4, minus, sine, left parenthesis, 4, theta, right parenthesis, minus, theta, cosine, left parenthesis, theta, right parenthesisr=−4−sin(4θ)−θcos(θ) with the shortest distance from the pole. Round to the nearest thousandth.

Solution

To find the value of θ\theta in the interval 0θπ20 \leq \theta \leq \frac{\pi}{2} that corresponds to the point on the curve r=4sin(4θ)θcos(θ)r = -4 - \sin(4\theta) - \theta \cos(\theta) with the shortest distance from the pole (origin), we need to find the minimum value of the function r(θ)r(\theta) within the given interval. The distance from the pole is minimized when r(θ)r(\theta) is minimized.

Steps to solve:

  1. Define the function: r(θ)=4sin(4θ)θcos(θ)r(\theta) = -4 - \sin(4\theta) - \theta \cos(\theta)

  2. Take the derivative of r(θ)r(\theta) with respect to θ\theta to find the critical points: drdθ=4cos(4θ)cos(θ)+θsin(θ)\frac{dr}{d\theta} = -4 \cos(4\theta) - \cos(\theta) + \theta \sin(\theta)

  3. Set the derivative equal to zero to find critical points: 4cos(4θ)cos(θ)+θsin(θ)=0-4 \cos(4\theta) - \cos(\theta) + \theta \sin(\theta) = 0 Solve this equation for θ\theta.

  4. Evaluate r(θ)r(\theta) at the critical points and the endpoints of the interval 0θπ20 \leq \theta \leq \frac{\pi}{2}.

  5. Determine the minimum value of r(θ)r(\theta) within the interval by comparing the values obtained in the previous step.

  6. Round θ\theta corresponding to the minimum r(θ)r(\theta) to the nearest thousandth.

Let me perform these calculations for you.The value of θ\theta in the interval 0θπ20 \leq \theta \leq \frac{\pi}{2} that corresponds to the point on the curve with the shortest distance from the pole is approximately θ=0.438\theta = 0.438 radians. The corresponding minimum value of r(θ)r(\theta) is approximately 5.380-5.380.

Would you like more details or have any questions? Here are five related questions you might consider:

  1. How does changing the interval affect the value of θ\theta that minimizes r(θ)r(\theta)?
  2. What is the significance of the function r(θ)r(\theta) in polar coordinates?
  3. Can you find the second derivative to confirm whether this point is a minimum?
  4. How would the solution change if the function r(θ)r(\theta) were different?
  5. How does the periodic nature of the trigonometric functions affect the results?

Tip: When dealing with trigonometric functions, it's useful to visualize the graph to better understand the behavior of the function over the given interval.

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Math Problem Analysis

Mathematical Concepts

Calculus
Trigonometry
Minimization

Formulas

Polar coordinates
Derivative

Theorems

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Suitable Grade Level

Advanced High School / Undergraduate