How to plot a line with specific line slope ?

i have a one coordinates (x1,y1).

(actually i have a lot of coordinates.)

what i want to know is how to plot a line with specific line slope and (x1,y1).

thanks!

Answer 1

[Voss]

You have to decide where the plotted line segment should start and end.

Here's one way you might do that, which is to plot the line between two points whose x-coordinates are a certain amount away from x1:

x1 = 3;
y1 = 4;

% slope = 2:
m = 2;

% plot the point (x1,y1):
plot(x1,y1,'ko','MarkerFaceColor','k');
hold on

% plot a line segment with x going from x1-1 to x1+1.
% note that if x changes by 1, then y changes by m
% (that's the definition of the slope of a line):
plot(x1+[-1 1],y1+m*([-1 1]),'b','LineWidth',2)

% another line segment going from x1-4 to x1+2,
% with the same slope:
plot(x1+[-4 2],y1+m*([-4 2]),'--r')

axis equal

[Anubhav]

I have been trying figure out this, and this seems to be the best solution yet. Kudos!

Answer 2

[Sam Chak]

But you can only determine the slope if you know the coordinates of the adjacent points.

Are you trying to plot the vector of a particular point when its coordinate is given?