hey guys. Something's been bothering me.. Well two things..(adsbygoogle = window.adsbygoogle || []).push({});

First of all, when looking at an algebraic equation and testing to see if its a function, why can X be squared, but not Y? our professor and book, gives the impression that something like:

x^2 +y =1 is a function

while..

-x +y^2 = 1 is NOT a function

Why is this? I know that in a function, the domain can't be linked to two or more elements in the range.. is that what the second equation is saying? Is the x and y in these equations representations of the domain and range of a function?

My 2nd main question is, what is the difference in saying

f(x) = 1-x^2 and saying y = 1-x^2?

Are they both the same thing? Why does y = f(x) anyway? I thought that f(x) was just the name of the function being presented, but then I saw my professor draw a graph, with the 'Y' letter on the yaxis replaced by the f(x) notation and was severely confused!

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# Testing to see if an Equation is a function

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