How to write equation a for X and Y

How to write equation a for X and Y using the below image (how to obtain X and Y)

[Rik]

I don't understand the constraints of your question, nor what makes this a Matlab question. You have a direct equation to obtain X and Y, so what is your problem?

Answer 1

[Image Analyst]

Try this:

xy = [xj-xi; yj-yi];
rotationMatrix = [cos(theta), sin(theta); sin(theta), -cos(theta)]
XY = rotationMatrix * xy;
X = XY(1);
Y = XY(2);