Expression 3: "z" equals 9 "x" "y" left brace, 2 squared less than or equal to "x" squared plus "y" squared less than or equal to 6 squared , right brace left brace, 0 less than or equal to "x" , right brace left brace, 0 less than or equal to "y" , right brace left brace, "y" greater than or equal to 1 third StartRoot, 3 , EndRoot "x" , right bracez=9xy22≤x2+y2≤620≤x0≤yy≥133x
3
Expression 4: 0 less than "z" less than or equal to 9 "x" "y" left brace, "x" equals tan left parenthesis, "a" , right parenthesis "y" , right brace left brace, 2 squared less than or equal to "x" squared plus "y" squared less than or equal to 6 squared , right brace0<z≤9xyx=tanay22≤x2+y2≤62
4
Expression 5: left parenthesis, "t" times sin left parenthesis, "a" , right parenthesis , "t" times cos left parenthesis, "a" , right parenthesis , 9 "t" squared sin left parenthesis, "a" , right parenthesis cos left parenthesis, "a" , right parenthesis , right parenthesist·sina,t·cosa,9t2sinacosa
domain t Minimum: 22
less than or equal to "t" less than or equal to≤t≤
