MHB Is a Line Parallel to the Y-Axis a Function?

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A line parallel to the Y-axis cannot be classified as a function because it does not meet the vertical line test, where each x-coordinate must correspond to only one y-coordinate. The discussion centers on finding point Q, which is equidistant from the x-axis and passes through point P (1, -2). The solution indicates that Q is located at (1, 2), maintaining a constant x-coordinate of 1. The exercise highlights a misunderstanding in the teaching of functions in the context of Calculus 1. Overall, while the line can be geometrically described, it does not qualify as a function.
Chipset3600
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Hello guys, i hv doubt in this question:

"1-Mark the point Q, such that the line through P (1, -2) and Q is perpendicular to the x-axis (the horizontal axis) so that the point Q to point P is equidistant from the axis x. Find the equation of the line."If the line be perpendicular of the X axis, so will be parallel of the Y axis. A line parallel to the axis Y can be a function?
OBS: Sorry about my bad technical English.
 
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It can't be a function, but it can be geometrically described. Its property is that the $x$ coordinate is constant. Since it has to pass through $P$, then we necessarily have $x=1$. Since it has to be equidistant to the axis, we need to find the distance of $P$ to it, which is simply the absolute value of the $y$ coordinate. By drawing a figure you can see that the solution is $Q=(1,2)$.
 
So i guess my teacher didnt elaborate good this exercice, becos we are in Calculus 1, and we are studying as function of X
Fantini said:
It can't be a function, but it can be geometrically described. Its property is that the $x$ coordinate is constant. Since it has to pass through $P$, then we necessarily have $x=1$. Since it has to be equidistant to the axis, we need to find the distance of $P$ to it, which is simply the absolute value of the $y$ coordinate. By drawing a figure you can see that the solution is $Q=(1,2)$.
 
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