Khan/khan-exercises — Issue #4814: Parabola intuition 3 - I don't think your "calculation" of focus is correct.
Author: KhanBugz
Created: 2011-10-22 21:58:53+00:00
State: open
Labels: chrome, win7

Reporter: tommyunger@gmail.com

It appears the focus of the parabola is: (1/2, 11/8), but the tool says (1, 11/8). Here's a screen shot:
http://grab.by/b6MD

[parabola_intuition_3.html?seed=81&problem=0](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/parabola_intuition_3.html?seed=81&problem=0&debug)

[["11/8","5/8","1","0.5","1.375","-0.625"],["5/8","11/8","1","0.5","1.375","-0.625"]]

Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.1 (KHTML, like Gecko) Chrome/14.0.835.202 Safari/535.1

MathJax is loaded, ready, queue length: 0