How to find x,y coordinates.

I have to find x,y coordinates for 3 data points where the slope of my function changes. When I just click on the points, I can see the x,y coordinates but I was wondering if there is a better way to do it that will be more accurate. I created this plot like this plot(distance,T,'-k')

[Torsten]

Depends on how the plot was created ...

[Torsten]

So "distance" and "T" are known arrays of numerical values ?

Answer 1

[Sulaymon Eshkabilov]

(1) Using the data to be plotted

y = @(t)2*t.^2+3*t-5;
t = 0:2:8;
f = y(t);
tnew = 0:.2:8;
y = interp1(t, f, tnew);
figure
plot(t,f, 'k-')
hold on
plot(t,f, 'ro', 'markerfacecolor', 'y', 'MarkerSize', 9)
xlabel('t')
ylabel('y(t)')
hold off

(2) Graphical and approximate approach is ginput()

y = @(t)2*t.^2+3*t-5;
t = 0:2:8;
f = y(t);
tnew = 0:.2:8;
y = interp1(t, f, tnew);
figure
plot(tnew,y, 'k-', 'linewidth', 2)

N = 4;   % Number of data points to be located with ginput()
[xx, yy] = ginput(N);