I recently started with 2d transformations in my class. I was just working with a program when I realized the formula I am using rotates the object spirally inwards. I have no idea whats over about this. I expected my figures to be rotated about a point but rather they all deform with every degree of rotation. I used a single point & realized that the point was moving spirally inwards with every degree I moved.
Can someone help me & let me know why it falls in rather than following circle or if that is what is expected of 2d rotation. I somehow felt its something related to how we view in 2d plane (or the imaginary z index here) but simply can't get around it.
I am following wiki & talking about this :
x' = xcosθ − ysinθ
y' = xsinθ + ycosθ