A question on plotting functions on a graph

[#neutrino]

when i was reading a supplementary notes doc from open course ware fro MIT on single variable calculus there was a description about a graphical representation of a single valued function as
" if each line parallel to the y- axis and which passes through a point in the domain intersects the graph at only one point then our function is single valued " my point is since it is a line drawn parallel to the y- axis for each input there will be several outputs ,therefore how come it is a function at all?

 

[BvU]

Make a drawing and indicate what you read from this sentence. It seems to me you misunderstand the statement...

 

[#neutrino]

thanks got it

 

[BvU]

You're welcome.