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Annotation of /trunk/NationalProblemLibrary/272/setStewart14_2/problem_5.pg

 1 : jj 94 ## -*- perl -*- ## 2 : ## Line above puts emacs in perl mode 3 : ## 4 : ## Description 5 : ## This is a generic problem template 6 : ## EndDescription 7 : 8 : DOCUMENT(); 9 : loadMacros("PG.pl", 10 : "PGbasicmacros.pl", 11 : "PGchoicemacros.pl", 12 : "PGanswermacros.pl", 13 : "PGauxiliaryFunctions.pl", 14 : "PGgraphmacros.pl", 15 : "Dartmouthmacros.pl"); 16 : 17 : 18 : ## Do NOT show partial correct answers 19 : $showPartialCorrectAnswers = 0; 20 : 21 :$r = random(2, 20); 22 : 23 : @answers = ( 24 : "$$LBRACE (x,y) | -x \le y \le x RBRACE$$", 25 : "$$LBRACE (x,y) | -x < y < x RBRACE$$", 26 : "$$LBRACE (x,y) | x \ge y RBRACE$$", 27 : "$$LBRACE (x,y) | -x < y \le x RBRACE$$", 28 : "the whole xy-plane", 29 : ); 30 : @permutation = NchooseK(5,5); 31 : 32 : ## Ok, we are ready to begin the problem... 33 : ## 34 : TEXT(beginproblem()); 35 : 36 : 37 : BEGIN_TEXT 38 : $BR 39 : 40 : The largest set on which the funtion $$f(x,y) = \sqrt{x+y} - \sqrt{x-y}$$ 41 : is continuous is \{ans_rule()\} 42 : 43 :$PAR 44 : END_TEXT 45 : 46 : BEGIN_TEXT 47 : \{ (OL(@answers[@permutation])) \} 48 : 49 : END_TEXT 50 : 51 : @inverted_alphabet = @ALPHABET[invert(@permutation)]; 52 : 53 : ANS(str_cmp(\$inverted_alphabet[0])); 54 : 55 : ENDDOCUMENT(); 56 : 57 : 58 : 59 :