how to extend a straight line passing through two points until it meets the y axis of the Cartesian plane

53 vues (au cours des 30 derniers jours)
I have a graph of this type and I have created the straight line dashed in red that passes through the point of coordinates 0-0 and the point marked with the red dot. now I should extend this line until it meets the y axis, always maintaining the same inclination as the straight line. this is because then I need to identify the coordinates of the points of intersection between the straight line and the other curved lines with values 10 - 1 and 0.01.
how can I do? can anyone help me?
  2 commentaires
dpb le 8 Oct 2022
Attach data and code so folks have something to work with...nothing can do with just the image...
Ghazwan le 8 Oct 2022
It looks like you are doing this manually. It is way better to make a code for this line. With the code, we can make an equation for and find the intersection points.

Connectez-vous pour commenter.

Réponse acceptée

Star Strider
Star Strider le 8 Oct 2022
It already meets the y-axis at the origin (0,0).
If you want to extend it to , that is straightforward —
slope = -53634 / -234311;
intercept = 0;
yfit = -5E+5*slope + intercept
yfit = -1.1445e+05
plot([-5E+5 0], [yfit 0], '--r')
axis([-5E+5 1E+5 -3.1E+5 2.5E+5])
I do not have your contourf plot, so I cannot plot it with that as well.

Plus de réponses (1)

Image Analyst
Image Analyst le 8 Oct 2022
Is this like what you want?
x = [1, 5];
y = [2, 7];
plot(x, y, 'b.-', 'LineWidth', 2, 'MarkerSize', 30)
grid on;
xlim([0, 6])
ylim([0, 8])
% Fit a line through x and y
coefficients = polyfit(x, y, 1);
% Get the value on the y axis, which is when x=0.
x0 = 0;
y0 = polyval(coefficients, x0)
y0 = 0.7500
% Plot a line from the y axis to the point [x1, y1]
hold on;
plot([x0, x(1)], [y0, y(1)], 'r-', 'LineWidth', 2)


En savoir plus sur Lighting, Transparency, and Shading dans Help Center et File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by