Expression 4: distance left parenthesis, left parenthesis, cos "x" , sin "x" , right parenthesis plus left parenthesis, cos "y" , sin "y" , right parenthesis , left parenthesis, 0 , 0 , right parenthesis , right parenthesis less than or equal to 1 left brace, 0 less than or equal to "x" less than or equal to 2 pi , right brace left brace, 0 less than or equal to "y" less than or equal to 2 pi , right bracedistancecosx,sinx+cosy,siny,0,0≤10≤x≤2π0≤y≤2π
4
Expression 5: cosine left parenthesis, "x" minus "y" , right parenthesis less than or equal to negative 1 halfcosx−y≤−12