Question

Question #c3676

Answer 1

See explanation.

Explanation:

A function `y=f(x)` is an assignment where for every value of `x` there is only one corresponding value of `f(x)`

Explanation 1

The vertical line goes through ever point `(x_0,y)` for a constant `x_0` and all real `y`. This means that for one argument `x_0` there are infinitely many values `y` which does not fulfill the condition defining a function `y=f(x)`

Explanation 2

Other way to justify such imposibility is that for every linear function `y=mx+b` `m` is the value of tangent of angle between the graph and `X` axis.

If we graph a vertical line we see that the angle between the graph and `X` axis is `90^o`, but `tan90` does not exist therfore there is no possible value of `m` for such graph.