8
votes
1answer
727 views

What are curves (generalized ellipses) with more than two focal points called and how do they look like?

An ellipse is usually defined as the locus of points so that sum of the distances to the two foci is constant. But what are curves called which are defined as the locus of points so that the sum of ...
1
vote
1answer
101 views

Point travels around curve

I wonder what does this mean: Point travels around curve. I try to figure out some math explanation in the book and I can't move forward because I can't understand these words. I can understand when ...
1
vote
1answer
308 views

What is a word to describe curves that have a tangent but are curved away from each other?

I'm writing a description that involves two curves behaving (approximately) as shown below. There aren't actually two intersections: they are mutually tangential. Also, I have many such curves, this ...
2
votes
1answer
293 views

Does anyone know the name of this curve?

I have come upon the curve with the following parametric equations: $$x(t)=\log(2+2\cos(t))/2$$ $$y(t)=t/2$$ for $-\pi<t<\pi$. It gives the image in the complex plane under $\log(1+z)$ of the ...