Connecting 3-points by arc

How can I plot an arc that can connect three-point in the x,y plane, the points are 2*1 matrix. Actually, I look to create a function so I can use it many times.

Answer 1

[Walter Roberson]

Note that this code considers the points to be unordered, and connects them in x order.

Also, this code is not designed to be able to handle vertical (or near vertical) connections. For example connect3([1;1], [1;3], [2,2]) will give it problems.

connect3(randn(2,1), randn(2,1), randn(2,1));
connect3(rand(2,1)*2, rand(2,1)*2, rand(2,1)*2);

function connect3(A, B, C)
  x = [A(1); B(1); C(1)];
  y = [A(2); B(2); C(2)];
  [x, idx] = sort(x);
  y = y(idx);
  p = polyfit(x, y, 2);
  xp = linspace(x(1),x(3),20);
  yp = polyval(p, xp);
  line(xp, yp);
end

[Abdulaziz Alnaghmoush]

Thank you so much

[darova]

This is parabola, not an arc

[Walter Roberson]

Oh? How is an arc defined? Is a parabola not a connected subset of a differentiateable function?

https://en.m.wikipedia.org/wiki/Curve#Differentiable_arc

[darova]

I thought arc is a part of circle

[Walter Roberson]

Nope, any curve that you can differentiate.