Points of intersection with polar equations

Click For Summary
SUMMARY

The discussion focuses on finding points of intersection between the polar equations r² = sin(2θ) and r² = cos(2θ). The key step involves setting sin(2θ) equal to cos(2θ), leading to the equation 2sin(θ)cos(θ) = cos²(θ) - sin²(θ). The user encounters difficulty in solving this equation but realizes that dividing by cos²(θ) simplifies the problem to solving tan(2θ) = 1. This approach effectively identifies the points of intersection.

PREREQUISITES
  • Understanding of polar coordinates and equations
  • Knowledge of trigonometric identities, particularly sin(2θ) and cos(2θ)
  • Familiarity with factoring and solving trigonometric equations
  • Basic skills in manipulating algebraic expressions
NEXT STEPS
  • Study the derivation and applications of polar equations
  • Learn about trigonometric identities and their proofs
  • Explore methods for solving trigonometric equations, including the use of tangent
  • Investigate graphical representations of polar curves and their intersections
USEFUL FOR

Students studying mathematics, particularly those focusing on trigonometry and polar coordinates, as well as educators looking for examples of solving polar equations.

n00neimp0rtnt
Messages
15
Reaction score
0

Homework Statement


I have to find all of the points of intersection of the curves...

r2 = sin(2θ)
r2 = cos(2θ)


The Attempt at a Solution



sin(2θ) = cos(2θ)
2sinθcosθ = cos2θ - sin2θ
2sinθcosθ - cos2θ = -sin2θ
cosθ(2sinθ - cosθ) = -sin2θ

This is where I'm having a problem, I'm not sure what to do from here.
 
Physics news on Phys.org
Why not just divide by cos2θ and solve tan2θ=1?
 
Aww. Yep you're right, thanks. (Today is not a math day for me; I temporarily forgot how to factor earlier, haha)
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 3 ·
Replies
3
Views
14K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
1
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 21 ·
Replies
21
Views
3K
Replies
1
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 4 ·
Replies
4
Views
9K