Math Problem Statement

 how many times does $r = 2 + sin(\theta)$ pass through x = 1 in cartesian coordinates?

Solution

To determine how many times the polar curve r=2+sin(θ)r = 2 + \sin(\theta) passes through x=1x = 1 in Cartesian coordinates, let's go through the following steps:

  1. Convert to Cartesian coordinates: In polar coordinates, we have: x=rcos(θ)andy=rsin(θ).x = r \cos(\theta) \quad \text{and} \quad y = r \sin(\theta). Since r=2+sin(θ)r = 2 + \sin(\theta), we can write: x=(2+sin(θ))cos(θ).x = (2 + \sin(\theta)) \cos(\theta).

  2. Set x=1x = 1: We are interested in when x=1x = 1, so we set up the equation: (2+sin(θ))cos(θ)=1.(2 + \sin(\theta)) \cos(\theta) = 1.

  3. Simplify the equation: Expanding this equation does not yield a simple factorization, but we can analyze it by testing specific values of θ\theta to see if they satisfy this equation.

  4. Test values of θ\theta in the range 0θ<2π0 \leq \theta < 2\pi:

    • If we substitute values of θ\theta where sin(θ)\sin(\theta) reaches extreme points, like θ=π2\theta = \frac{\pi}{2}, θ=3π2\theta = \frac{3\pi}{2}, θ=0\theta = 0, and θ=π\theta = \pi, we can determine when x=1x = 1.
    • Through testing and substitution, you will find that there are two solutions for θ\theta that satisfy x=1x = 1 in the interval 0θ<2π0 \leq \theta < 2\pi.

Thus, the curve r=2+sin(θ)r = 2 + \sin(\theta) passes through x=1x = 1 two times as θ\theta varies from 00 to 2π2\pi.

Would you like more details on each step?


  1. How do we convert polar equations to Cartesian coordinates in general?
  2. Why does setting x=1x = 1 help us find specific points on a polar curve?
  3. What are common strategies for testing trigonometric values when solving polar equations?
  4. How can symmetry in polar curves simplify solving such problems?
  5. Are there other ways to solve this without substituting specific θ\theta values?

Tip: When analyzing polar curves, try graphing the function to get a visual sense of how the curve behaves as θ\theta varies.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Polar Coordinates
Cartesian Coordinates
Trigonometry

Formulas

x = r * cos(\theta)
r = 2 + sin(\theta)

Theorems

Conversion from polar to Cartesian coordinates

Suitable Grade Level

Grades 10-12