[LON-CAPA-users] math rendering engine

[Stefan Bisitz]

And again... ;-)

Much better (the best?):

Don't use two variables, one for calculations and one for display. It's 
simpler, shorter and less error-prone to have only one variable:

<script type="loncapa/perl">
$function1 = "(x^2 - 1)^2";
$function2 = "sqrt(x^2 - 1)";
$function3 = "3/(2 + x^2)";
$function4 = "2/(3 + sqrt(1 + x))";
$example1=[...]
</script>

<startouttext />
<p>Give an example of two nontrivial functions <m>$ f $</m> and <m>$ g 
$</m> such that <m eval="on">$ (f \circ g)(x) = $</m> 
<algebra>$displayfunction</algebra>.</p>
[...]
<endouttext />


In general, store or calculate your formula in one variable using the 
1-dimensional "pocket calculator" notation. Reuse the same variable to 
display it by using the <algebra> tag (without any "$") which 
automatically renders in the preferred method.

Stefan Bisitz


On 19.01.2010 11:04, Stefan Bisitz wrote:
> Hi again,
> 
> Why "pre-parse" anyway?
> 
> Even better:
> 
> 1)
> <script type="loncapa/perl">
> [...]
> $displayfunction1 = '(x^2 - 1)^2';
> [...]
> 
> and 2)
> [...]
> such that <m eval="on">$ (f \circ g)(x) = $displayfunction $</m>.
> [...]
> 
> 
> Stefan Bisitz
> 
> 
> On 19.01.2010 10:32, Stefan Bisitz wrote:
>> Hi Justin,
>>
>> It's quite simple to solve your display issues. You parse the formula 
>> twice:
>> 1) $displayfunction1 = &xmlparse('<m>$(x^2 - 1)^2$</m>');
>> [...]
>>
>> 2) <m eval="on">$(f \circ g)(x) = $displayfunction $</m>
>>
>> Just change to
>> <m>$ (f \circ g)(x) = $</m> $displayfunction
>>
>> $displayfunction is already parsed and must not be included again in 
>> the <m> tag.
>>
>> tth as well as mimetex works now (tested on bleeding edge machine).
>>
>> And yes, please avoid to use jsmath hardcoded in the problem. Let the 
>> CCs or students decide.
>>
>> Stefan Bisitz
>>
>>
>>
>> On 19.01.2010 09:59, Justin Gray wrote:
>>> When displaying equations, setting the display attribute within the 
>>> <m> tag to "jsMath" is generally discouraged as it requires users to 
>>> have
>>> installed jsmath software on their computer and will override their 
>>> preferences on how math equations are displayed.
>>>
>>> I have tried viewing the problem below on several computers and 
>>> jsMath seems to be the only math rendering engine that lets me view 
>>> the equations properly. (With tth the equations do not show up at all 
>>> and with mimetex the equations are incomprehensible.) I am reluctant 
>>> to force users to jsMath for this problem. Perhaps there is another 
>>> way to remedy this problem?
>>>
>>> Any suggestions are appreciated.
>>>
>>> Thanks,
>>> Justin
>>>
>>> Justin Gray | Senior Lecturer
>>> Department of Mathematics | Simon Fraser University
>>> 8888 University Drive, Burnaby | V5A 1S6 | Canada
>>> Tel: +1 778.782.4237
>>>
>>> <problem>
>>> <script type="loncapa/perl">
>>> $function1 = "(x^2 - 1)^2";
>>> $function2 = "sqrt(x^2 - 1)";
>>> $function3 = "3/(2 + x^2)";
>>> $function4 = "2/(3 + sqrt(1 + x))";
>>> $displayfunction1 = &xmlparse('<m>$(x^2 - 1)^2$</m>');
>>> $displayfunction2 = &xmlparse('<m>$\sqrt{x^2 - 1}$</m>');
>>> $displayfunction3 = &xmlparse('<m>$\displaystyle \frac{3}{2 + 
>>> x^2}$</m>');
>>> $displayfunction4 = &xmlparse('<m>$\displaystyle \frac{2}{3 + \sqrt{1 
>>> + x}}$</m>');
>>> $example1=&xmlparse('Many answers are possible. One example would be 
>>> <m>$f(x) = x^2, \quad g(x) = x^2 - 1$</m>');
>>> $example2=&xmlparse('Many answers are possible. One example would be 
>>> <m>$f(x) = \sqrt{x}, \quad g(x) = x^2 - 1$</m>');
>>> $example3=&xmlparse('Many answers are possible. One example would be 
>>> <m>$f(x) = 3/x, \quad g(x) = 2 + x^2$</m>');
>>> $example4=&xmlparse('Many answers are possible. One example would be 
>>> <m>$f(x) = 2/(3 + x), \quad g(x) = \sqrt{1 + x}$</m>');
>>> $n = &random(1,4,1);
>>> $function = 
>>> &choose($n,"$function1","$function2","$function3","$function4");
>>> $displayfunction = 
>>> &choose($n,"$displayfunction1","$displayfunction2","$displayfunction3","$displayfunction4"); 
>>>
>>> $example = &choose($n,"$example1","$example2","$example3","$example4");
>>> </script>
>>>
>>> <startouttext /><p>Give an example of two nontrivial functions 
>>> <m>$f$</m> and <m>$g$</m> such that <m eval="on">$(f \circ g)(x) = 
>>> $displayfunction $</m>.</p>Enter your answer in the form 
>>> <p><b>expression1,expression2</b></p> where <m>$f(x) = $</m> 
>>> <b>expression1</b> and <m>$g(x) = $</m> 
>>> <b>expression2</b>.<p></p><endouttext />
>>>
>>> <mathresponse answerdisplay="$example" cas="maxima" args="$function" 
>>> id="11">
>>>     <answer>f(x) := RESPONSE[1];
>>> g(x) := RESPONSE[2];
>>> h(x) := LONCAPALIST[1];
>>> composition:is(trigsimp(f(g(x)) - h(x)) = 0);
>>> fnottrivial:is(not(f(x) = x));
>>> gnottrivial:is(not(g(x) = x));
>>> composition and fnottrivial and gnottrivial;</answer>
>>>     <textline readonly="no" size="20" />
>>>     <hintgroup showoncorrect="no">
>>>         <mathhint name="composition not equal" cas="maxima" 
>>> args="$function" id="12">
>>>             <answer>f(x) := RESPONSE[1];
>>> g(x) := RESPONSE[2];
>>> h(x) := LONCAPALIST[1];
>>> is(not(f(g(x)) = h(x)));</answer>
>>>         </mathhint>
>>> <hintpart on="composition not equal">
>>>     <startouttext /><p>Your example does not satisfy <m eval="on">$(f 
>>> \circ g)(x) = f(g(x)) = $displayfunction $</m>.</p><endouttext />
>>> </hintpart>
>>>     </hintgroup>
>>>     <hintgroup showoncorrect="no">
>>>         <mathhint name="f trivial" cas="maxima" id="13">
>>>             <answer>f(x) := RESPONSE[1];
>>> is(f(x) = x);</answer>
>>>         </mathhint>
>>> <hintpart on="f trivial">
>>>     <startouttext /><p>The question asks for nontrivial functions, 
>>> and so you cannot use <m>$f(x) = x$</m>.</p><endouttext />
>>> </hintpart>
>>>     </hintgroup>
>>>     <hintgroup showoncorrect="no">
>>>         <mathhint name="g trivial" cas="maxima" id="14">
>>>             <answer>g(x) := RESPONSE[2];
>>> is(g(x) = x);</answer>
>>>         </mathhint>
>>> <hintpart on="g trivial">
>>>     <startouttext /><p>The question asks for nontrivial functions, 
>>> and so you cannot use <m>$g(x) = x$</m>.</p><endouttext />
>>> </hintpart>
>>>     </hintgroup>
>>> </mathresponse>
>>> </problem>
>>>
>>>
>>>
>>
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