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Cleaned up &beginproblem and &ANS old style function reference.
1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> 2 <HTML> 3 <HEAD> 4 <TITLE>Source for problem 6</TITLE> 5 <META NAME="generator" CONTENT="BBEdit 5.0"> 6 </HEAD> 7 <BODY BGCOLOR="#FFFFFF"> 8 <PRE> 9 10 #Description 11 #KEYWORDS('derivatives', 'graphs') 12 # Identify the graphs of the function and the derivative 13 #EndDescription 14 15 &DOCUMENT; 16 17 18 loadMacros("PG.pl", 19 "PGbasicmacros.pl", 20 "PGchoicemacros.pl", 21 "PGanswermacros.pl", 22 "PGgraphmacros.pl"); 23 24 $a=random(0, 6.3, .1); 25 $b=random(1.1, 1.5, .1); 26 27 $dom = 4; 28 @slice = NchooseK(3,3); 29 30 @colors = ("blue", "red", "green"); 31 @sc = @colors[@slice]; #scrambled colors 32 @sa = ('A','B','C')[@slice]; 33 34 # define the functions and their derivatives. 35 # FEQ (Format EQuations) cleans up the writing of the functions (see FEQ in PGbasicmacros) 36 # Otherwise we would need to worry about the signs of $a, $b and so forth. 37 38 $f = FEQ("sin($a+$b*cos(x)) for x in <-$dom,$dom> using color:$sc[0] and weight:2"); 39 $fp = FEQ("cos($a+$b*cos(x))*(-$b)*sin(x) for x in <-$dom,$dom> using color=$sc[1] and weight:2"); 40 $fpp = FEQ("-sin($a+$b*cos(x))*$b*$b*sin(x)*sin(x)+ cos($a+$b*cos(x))*(-$b)*cos(x) for x in <-$dom,$dom> using color=$sc[2] and weight=2"); 41 42 $graph = init_graph(-4,-4,4,4,'axes'=>[0,0],'grid'=>[8,8]); 43 44 ($fRef,$fpRef,$fppRef) = plot_functions( $graph, 45 $f,$fp,$fpp 46 ); 47 48 # create labels 49 50 $label_point=-0.75; 51 $label_f = new Label ( $label_point,&{$fRef->rule}($label_point),$sa[0],"$sc[0]",'left') ; 52 # NOTE: $fRef->rule is a reference to the subroutine which calculates the 53 # function. It was defined in the output of plot_functions. It is used here 54 # to calculate the y value of the label corresponding to the function, 55 # and below to find the y values for the labels corresponding to the 56 # first and second derivatives. 57 58 $label_fp = new Label ( $label_point,&{$fpRef->rule}($label_point),$sa[1],"$sc[1]",'left') ; 59 $label_fpp = new Label ( $label_point,&{$fppRef->rule}($label_point),$sa[2],"$sc[2]",'left'); 60 61 # insert the labels into the graph 62 $graph->lb($label_f,$label_fp,$label_fpp); 63 64 $showPartialCorrectAnswers =0; 65 TEXT(beginproblem()); 66 TEXT(image(insertGraph($graph))); 67 TEXT(EV2(qq! 68 Identify the graphs A (blue), B( red) and C (green) as the graphs of a function and its 69 derivatives (click on the graph to see an enlarged image):$PAR 70 \{ans_rule(4)\} is the graph of the function $PAR 71 \{ans_rule(4)\} is the graph of the function's first derivative $PAR 72 \{ans_rule(4)\} is the graph of the function's second derivative $PAR 73 !)); 74 ANS(str_cmp( [@sa] ) ); 75 76 BEGIN_TEXT 77 $PAR 78 You can view the \{ htmlLink(alias("prob8.html"),"source", q!TARGET="source"!)\} for this problem. 79 or consult the \{ htmlLink("/webwork_system_html/docs/techdescription/pglanguage/index.html","documentation") \} for more details on the PG language. 80 END_TEXT 81 82 &ENDDOCUMENT; 83 84 85 86 </PRE> 87 </BODY> 88 </HTML>
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