How can I find a normal vector of a 2D line? [closed]

Question

I have a line with point a, (6, 12) and point b (45, 18).

To describe this line using vectors, the equation is L = [6, 12] +t [39, 6]

How would I go about finding the normal to this line?

Mckim

see also Given 2 points how do I draw a line at a right angle to the line formed by the two points? for an elaborate explanation – Phoenicia

possible duplicate of How do I calculate the normal vector of a line segment? – Scissile

I'm voting to close this question as off-topic because it is about mathematics, not programming. – Spud

Answer 1

From the Math StackExchange How do I calculate the normal vector of a line segment?:

if we define dx=x2-x1 and dy=y2-y1, then the normals are (-dy, dx) and (dy, -dx).

Phoenicia

so in this case the normal is l= [-6, 39] and [6, -39] – Mckim

your y2 is 18, your y1 is 12. so y2-y1 is 6. your x2 is 45 and your x1 is 6, so your x2-x1 is 39. so yes, (-dy,dx) is (-6,39) and (dy, -dx) is (6, -39). – Phoenicia