Verifying Lines are Perpendicular

In summary, two lines are perpendicular if they intersect at a 90-degree angle and have slopes that are negative reciprocals of each other. Two lines cannot be perpendicular if they have the same slope, and to verify algebraically, one can use the formula for finding the slope of a line. Graphically, perpendicular lines will intersect at a 90-degree angle and form a cross or "T" shape. Two lines can also be perpendicular if one is horizontal and the other is vertical, with slopes of 0 and undefined, respectively.
  • #1
odolwa99
85
0
Just a quick question here. Have I done this correctly? Do I need to factor in the 3 from L?

Many thanks.

Homework Statement



Q. Verify that the lines L: x -2y + 3 = 0 & K: 2x + y = 0 are perpendicular.

Homework Equations



The Attempt at a Solution



x(x) + y(y) = 0 => 1(2) + (-2)(1) = 2 - 2 = 0.
 
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  • #2
I have no idea what your solution is supposed to show, but verifying that two lines are perpendicular is easy. Just put them in y=mx+b form and compare them. If their slopes are opposite and reciprocal (2/3, -3/2 for example), then they are perpendicular.
 
  • #3
Ok, thank you.
 

1. How do you know if two lines are perpendicular?

In order for two lines to be perpendicular, they must intersect at a 90-degree angle. This means that the slope of one line must be the negative reciprocal of the slope of the other line. In other words, if one line has a slope of m, the other line must have a slope of -1/m.

2. Can two lines be perpendicular if they have the same slope?

No, two lines cannot be perpendicular if they have the same slope. As mentioned before, for two lines to be perpendicular, their slopes must be the negative reciprocal of each other. If two lines have the same slope, they are parallel and do not intersect at a 90-degree angle.

3. How can you verify that two lines are perpendicular algebraically?

To verify that two lines are perpendicular algebraically, you can use the formula for finding the slope of a line: m = (y2 - y1) / (x2 - x1). Plug in the coordinates of two points on each line and calculate the slopes. If the slopes are negative reciprocals of each other, the lines are perpendicular.

4. What is the graphical representation of perpendicular lines?

Graphically, perpendicular lines will intersect at a 90-degree angle and form a cross or "T" shape. The slopes of the lines will also be negative reciprocals of each other. Additionally, if you were to extend the lines infinitely, they would never intersect.

5. Can two lines be perpendicular if one is horizontal and the other is vertical?

Yes, two lines can be perpendicular if one is horizontal and the other is vertical. In this case, the horizontal line would have a slope of 0 and the vertical line would have an undefined slope. Their slopes would be negative reciprocals of each other (-1/0 and 0/-1, respectively).

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