Copie de Bijective Function & Inverses

How to show to students that a function that is not bijective will not have an inverse
Is the function y = x^2 + 1 injective? Surjective? Bijective?[br]How do we find the image of the points A - E through the line y = x?[br]How then can we check to see if the points under the image y = x form a function?

Information: Copie de Bijective Function & Inverses