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<p>Hi Gene,</p>
<p>most likely the problem is one of number representation (which
contributes to rounding errors).</p>
<p>The binary representation of $Av+0.05 is (by which I mean "the
result of binary representation of $Av plus binary respresentation
of 0.05 as a binary")<br>
</p>
<p>10.101100110011001100110011001100110011001100110011001</p>
<p>whereas the binary representation of 2.7 is</p>
<p>10.101100110011001100110011001100110011001100110011010</p>
<p>Both binary numbers differ only in the last two digits and the
second one is larger. That explains why 2.7 is not accepted.</p>
<p>I have done the computations on 64-bit machine which likely
matches your server's resolution.</p>
<p>I hope this is of help.</p>
<p>Peter<br>
</p>
<div class="moz-cite-prefix">Am 22.09.2019 um 02:51 schrieb Harding,
Gene L:<br>
</div>
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<p class="MsoNormal"><span style="color:#1F497D">Hi everyone,<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I have a quiz problem in LC that seems to
be doing some odd things with the rounding. I have
successfully recreated the problem reported by one of my
students, but cannot figure out why it happens.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The answer to the problem (part c) is 2.65
on the dot. The problem requests an answer with one place
after the decimal, and the tolerance is +/- 0.05. In this
case, since the value computes to exactly 2.65, LC should take
anything from 2.6 to 2.7. In fact, in author view LC indicates
it will take anything from 2.6 to 2.7:<o:p></o:p></p>
<p class="MsoNormal"><img style="width:2.8541in;height:.3541in"
id="Picture_x0020_1"
src="cid:part1.99A52A7F.672D8F68@ostfalia.de" class=""
width="274" height="34"><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The trouble is that 2.6 works, 2.65 works,
but 2.7 does not.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This is the Perl script calculation (Rf=33,
Ri=20):<o:p></o:p></p>
<p class="MsoNormal">$Av = 1+$Rf/$Ri; # Gain
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This is the response code:<o:p></o:p></p>
<p class="MsoNormal"><numericalresponse unit="" format="1f"
answer="$Av" id="3"><o:p></o:p></p>
<p class="MsoNormal"> <responseparam name="tol"
type="tolerance" default="0.05" description="Numerical
Tolerance" /><o:p></o:p></p>
<p class="MsoNormal"> <textline readonly="no"
spellcheck="none" /><o:p></o:p></p>
<p class="MsoNormal"></numericalresponse><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Any idea what the problem is? I am baffled.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Best regards,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Gene L. Harding, PE<o:p></o:p></p>
<p class="MsoNormal">Associate Professor of ECET<o:p></o:p></p>
<p class="MsoNormal">Purdue University<o:p></o:p></p>
<p class="MsoNormal">574-520-4190<o:p></o:p></p>
<p class="MsoNormal"><a
href="https://polytechnic.purdue.edu/south-bend/"
moz-do-not-send="true">https://polytechnic.purdue.edu/south-bend/</a><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<br>
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<pre class="moz-signature" cols="72">--
Peter Riegler
Fakultät Informatik
Ostfalia Hochschule für angewandte Wissenschaften
- Hochschule Braunschweig/Wolfenbüttel
Salzdahlumer Str. 46/48
38302 Wolfenbüttel
Tel 05331 939 31540
Fax 05331 939 31542
Web <a class="moz-txt-link-abbreviated" href="http://www.ostfalia.de/pws/riegler">www.ostfalia.de/pws/riegler</a> </pre>
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