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I believe that the definition of the parameter t in the Equations section may be incorrect. I think t should the (radian) angle from the x-axis to the line from the origin going through the centre of the rolling circle. I could easily derive the given parametric equations for x and y using this definition, whereas I got nowhere using the given definition: "t is the angle at the origin from the horizontal axis to the ray to a point on the cardioid." Robedavi42 ( talk) 18:06, 7 August 2016 (UTC)
Move the graph to the top?
Huh?? Why move a chunk of page content off to a subpage?
Dysprosia
01:27, 19 May 2005 (UTC)
I'm no geometer, but it looks like the cross-section of a globe tomato to me.
It's a butt... —Preceding
unsigned comment added by
84.238.88.87 (
talk)
08:49, 12 January 2008 (UTC)
Plums are almost always an oval shape. Peaches and apples are much closer to the shape than plums. Apples though are usually round and match the shape perfectly, especially so if they are the sweeter ones that supermarkets sell and people like to eat. Apples are the only decent fit when the cardioid is three dimensions because there is no groove in them (peaches and plums have a groove from top to bottom.)
Tomatoes don't tend to have a stalk recessed into the fruit. Cherries do but they aren't always round and people think of them in pairs. Scottonsocks ( talk) 03:57, 9 March 2011 (UTC)
I do not understand how the images can be understood - what are x and y? -- Abdull 16:11, 23 May 2006 (UTC)
IMHO it should be merged with/into Heart (Symbol) -- Wulf 03:17, 5 June 2006 (UTC)
If you want to know r=4*sin-1((sin(O/2)(3/2))) graphs a better "love heart" shape [Matthew Schimpf 7:15 11 March 2009] —Preceding unsigned comment added by 121.221.2.176 ( talk) 10:17, 11 March 2009 (UTC)
It's a nephroid. I have solved this problem. —Preceding unsigned comment added by 84.2.80.109 ( talk) 11:49, 29 October 2007 (UTC)
It should be possible to simplify and summarize the material in Cardioid/Proofs so that it can be merged into the main article. In addition, the article name 'Cardioid/Proofs' does not conform to Wikipedia naming conventions. Therefore I propose that the other article be merged with this article.-- RDBury ( talk) 04:59, 12 December 2009 (UTC)
Other sources give them as:
x = a cos t (1 - cos t) y= a sin t (1 - cos t)
These are not equivalent to those shown in the article. —Preceding unsigned comment added by 70.179.4.83 ( talk) 08:34, 20 November 2010 (UTC)
Also, the equation for the area enclosed by a cardioid appears to be incorrect. Instead of A = 6*pi*r^2, isn't it A = 3*pi*r^2/2? Or am I off my rocker? — Preceding unsigned comment added by 74.248.242.76 ( talk) 11:53, 7 October 2011 (UTC)
Given the parametric equations used in the article, I think the arc length should be 16a not 8a. The 8a length relates to the parametric equations: x = a cos t (1 - cos t) y= a sin t (1 - cos t) which describe a smaller cardioid that the parametric equations shown in this article. Also, the formula for area will need to be adjusted. —Preceding unsigned comment added by 70.179.4.83 ( talk) 19:33, 20 November 2010 (UTC)
In the equations, for example; x = a(2cos(t)- cos(2t)) Is t the angle? Is it in degrees or radians? — Preceding unsigned comment added by 64.7.132.78 ( talk) 14:11, 13 November 2015 (UTC)
DOESN"T THE CARDIOID LOOK LIKE A BUTT? 108.66.234.157 ( talk) 22:45, 29 June 2016 (UTC)
Hi
I would like to add new section:
Points
What do you think aboyt it ? -- Adam majewski ( talk) 09:25, 21 June 2020 (UTC)
References