Question 213768
Is a circle a 'function' - it does not pass the vertical line test.  tks!


Yes.  You are correct.  But it is an equation like {{{x^2+y^2=1}}} centered at (0,0) or radius 1.  So at x=0 then y has two possible values at +1 and -1.


Hope that was helpful!.


I hope the above steps were helpful. 

 
And good luck in your studies!


For free Step-By-Step Videos on Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra or for Trigonometry visit http://www.FreedomUniversity.TV/courses/Trigonometry.


Respectfully,
Dr J