• Support PF! Buy your school textbooks, materials and every day products Here!

Representing a Cardioid

  • Thread starter darkblue
  • Start date
  • #1
30
0

Homework Statement



Show that the cardioid r=a(1+cos(theta)) can be represented by r=2acos2(theta/2), 0<=theta<=2pi (theta is between 0 and 2pi).

Homework Equations





The Attempt at a Solution



I'm pretty sure I have to equate the two expressions, but I haven't been able to do this. Then I thought of converting both of them to cartesian form (and seeing if they have the same equation) but that's turning into a bit of a mess. Any guidance would be greatly appreciated!
 

Answers and Replies

  • #2
236
0
Those are trig functions. There are lots of identities involving trig functions. One of them might be helpful.
 

Related Threads on Representing a Cardioid

  • Last Post
Replies
4
Views
3K
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
2
Views
4K
  • Last Post
Replies
13
Views
920
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
1
Views
2K
Replies
6
Views
2K
Replies
3
Views
13K
Replies
7
Views
16K
Replies
1
Views
1K
Top