Here, t is constant distance of point P. a is original angle of the point and b is the rotation.

x1= r cos (a+b) = r cos a r cos b – r sin a sin b

y1= r sin (a+b) = r cos a r sin b +r sin a cos b

x= r cos a

y= r sin b

=> x1= x cos b – y sin b

y1= x sin b + y cos b

In Matrix form:

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