Which coordinate of C changes as you move it along the vertical line?
Which coordinate of C does not change as you move it?
If we denote the point A as (a,b) and C as (c,d). Then we must have
What are the features of all the points on the vertical line?
Supposing you have put A as (-4,-3) and move C away from A downwards what will happen?
Supposing you have put the point A at (-1,5) and move C away from it upwards what will happen?
[size=150][color=#38761d]Since all the points of a vertical line have the same x-coordinate we can write all the points on it as a set [/color][math]\left\{\left(x,y\right):x=c\right\}[/math][color=#38761d] where c is the numerical value of all the x-coordinates. [br]We therefore define the equation of a line parallel to y-axis as x=c.[/color][/size]
What is the equation of line parallel to y-axis and passing through the point (2,3)?
If the point (2,3) lies on the line x=c then what is the value of c?
If [math]0<\theta<\pi[/math] then for what value of [math]\theta[/math] the line [math]x=\tan\theta[/math] will not be vertical?
Out of the points A(1,2), B(2,3) , C(3,2), D(1,2) which lie on the vertical line x=1?