I have a point in a rectangle that I need to rotate an arbitrary degree and find the x y of the point. How can I do this using javascript.

Below the x,y would be something like 1,3 and after I pass 90 into the method it will return 3,1.

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Basically I am looking for the guts to this method

function Rotate(pointX,pointY,rectWidth,rectHeight,angle){
   /*magic*/    
   return {newX:x,newY:y};
}