Is a Quadratic equation a function? The definition of a function is "A function is a relation in which there is never more then one value of the dependent variable for every value of the independent variable." 
Since a quadratic equation has two solutions for every input does this mean that the quadratic is not a function?

The function $f(x)=ax^2+bx+c$ is a quadratic function.
Now, if you try to solve a quadratic equation, you get often two solutions, but this is not the same as calculating the function. What does this actually shows is that the quadratic function takes many values twice, and in particular doesn't have an inverse.
