Graph r = 4 cos (20) without a calculator. Then use a calculator to find the length of the arc forming one petal. 0

Trigonometry (MindTap Course List)
8th Edition
ISBN:9781305652224
Author:Charles P. McKeague, Mark D. Turner
Publisher:Charles P. McKeague, Mark D. Turner
Chapter8: Complex Numbers And Polarcoordinates
Section: Chapter Questions
Problem 8CLT
icon
Related questions
Question
### Problem 2

**Task:**
- Graph \( r = 4 \cos(2\theta) \) without a calculator.
- Then use a calculator to find the length of the arc forming one petal.

**Instructions:**
1. **Graphing \( r = 4 \cos(2\theta) \):**
   - Start by understanding that this is a polar equation where \( r \) (radius) is a function of \( \theta \) (angle).
   - The equation \( r = 4 \cos(2\theta) \) represents a polar curve known as a "four-leaved rose." It features a periodic, sinusoidal pattern with four symmetrical petals.
   - To sketch the graph, calculate the values of \( r \) for various \( \theta \) values across one full period \( [0, 2\pi] \). Note the characteristic symmetry.

2. **Finding the arc length of one petal with a calculator:**
   - To calculate the length of the arc forming one petal, use the formula for the arc length \( S \) in polar coordinates:
     \[
     S = \int_{a}^{b} \sqrt{ \left( \frac{dr}{d\theta} \right)^2 + r^2 }\, d\theta
     \]
   - Substitute \( r = 4 \cos(2\theta) \) and find the derivative \( \frac{dr}{d\theta} \).
   - Integrate this expression over the limits corresponding to one petal.

This task requires both manual graphing skills and proficiency in calculus to find the arc length accurately.
Transcribed Image Text:### Problem 2 **Task:** - Graph \( r = 4 \cos(2\theta) \) without a calculator. - Then use a calculator to find the length of the arc forming one petal. **Instructions:** 1. **Graphing \( r = 4 \cos(2\theta) \):** - Start by understanding that this is a polar equation where \( r \) (radius) is a function of \( \theta \) (angle). - The equation \( r = 4 \cos(2\theta) \) represents a polar curve known as a "four-leaved rose." It features a periodic, sinusoidal pattern with four symmetrical petals. - To sketch the graph, calculate the values of \( r \) for various \( \theta \) values across one full period \( [0, 2\pi] \). Note the characteristic symmetry. 2. **Finding the arc length of one petal with a calculator:** - To calculate the length of the arc forming one petal, use the formula for the arc length \( S \) in polar coordinates: \[ S = \int_{a}^{b} \sqrt{ \left( \frac{dr}{d\theta} \right)^2 + r^2 }\, d\theta \] - Substitute \( r = 4 \cos(2\theta) \) and find the derivative \( \frac{dr}{d\theta} \). - Integrate this expression over the limits corresponding to one petal. This task requires both manual graphing skills and proficiency in calculus to find the arc length accurately.
Expert Solution
steps

Step by step

Solved in 3 steps with 3 images

Blurred answer
Recommended textbooks for you
Trigonometry (MindTap Course List)
Trigonometry (MindTap Course List)
Trigonometry
ISBN:
9781305652224
Author:
Charles P. McKeague, Mark D. Turner
Publisher:
Cengage Learning