Expression 1: "y" cosine left parenthesis, "a" , right parenthesis plus "x" sine left parenthesis, "a" , right parenthesis equals floor left parenthesis, "x" cos left parenthesis, "a" , right parenthesis minus "y" sin left parenthesis, "a" , right parenthesis , right parenthesis plus "x" cosine left parenthesis, "a" , right parenthesis minus "y" sine left parenthesis, "a" , right parenthesisycosa+xsina=floorxcosa−ysina+xcosa−ysina