Question 633838
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The slope of any linear equation of the form *[tex \LARGE x\ =\ a] is undefined.  The slope of any parallel to *[tex \LARGE x\ =\ a] is also undefined.  The slope of any perpendicular to *[tex \LARGE x\ =\ a] is zero, i.e. a horizontal line.


The essential characteristic of a vertical line is that the *[tex \LARGE x]-coordinate of every point is the same as the *[tex \LARGE x]-coordinate of every other point.


The equation of a line parallel to *[tex \LARGE x\ =\ a] passing through *[tex \LARGE (x_1,y_1)] is then *[tex \LARGE x\ =\ x_1]


The essential characteristic of a horizontal line is that the *[tex \LARGE y]-coordinate of every point is identical to the *[tex \LARGE y]-coordinate of every other point.


The equation of a line perpendicular to *[tex \LARGE x\ =\ a] passing through *[tex \LARGE (x_1,y_1)], is then *[tex \LARGE y\ =\ y_1]



John
*[tex \LARGE e^{i\pi}\ +\ 1\ =\ 0]
My calculator said it, I believe it, that settles it
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