<html>
<head>
<meta http-equiv="Content-Type" content="text/html;
charset=windows-1252">
</head>
<body>
<div class="moz-cite-prefix">On 7/10/20 1:57 PM, wrote:<br>
</div>
<blockquote type="cite"
cite="mid:a1724f1fb767415fb5d56c9599754747@CO2PR01MB1976.prod.exchangelabs.com">
<meta http-equiv="Content-Type" content="text/html;
charset=windows-1252">
<div dir="ltr">
<div data-ogsc="" style="">
<div>Hi dr pounds. I’m still confused on what to put for the
bound, and the x. Currently it’s 50/50 for me to get the
right x. On quiz 7 when I type
1.11-((2x)^2)/((.5-2x)^2)(.5-x) </div>
<div dir="ltr"><br>
</div>
<div dir="ltr">The bound should be {0,.5} right? Because .5
minus .5 is 0. But I end up getting .375 instead of the
correct x value. <br>
</div>
</div>
</div>
</blockquote>
<blockquote type="cite"
cite="mid:a1724f1fb767415fb5d56c9599754747@CO2PR01MB1976.prod.exchangelabs.com">
<div dir="ltr">
<div data-ogsc="" style="">
<div dir="ltr"><br>
</div>
<div dir="ltr"><br>
</div>
</div>
</div>
</blockquote>
<p><br>
</p>
<p>In your example the bound would be {0,0.25} because
(0.5-2(0.25))=0.</p>
<p>Let me set up your example and provide my three rules for setting
the bounds and how to set the initial value of <img alt="$x$"
style="vertical-align: middle;"
src="cid:part1.8E42435D.18A7294B@mercer.edu">.</p>
<p>Here is what you are trying to solve...</p>
<p><img alt="$1.11=\frac{(2x)^2}{(0.5-2x)^2(0.5-x)}$"
style="vertical-align: middle;"
src="cid:part2.DE0AA7B7.1D01D00E@mercer.edu"></p>
<p><br>
</p>
<p>To look for the bounds:</p>
<p>1. Isolate your search ONLY to the terms with negative signs in
them. In this case that is <img alt="$(0.5-2x)$"
style="vertical-align: middle;"
src="cid:part3.AE1FE561.9BA6E204@mercer.edu"> and <img
alt="$(0.5-x)$" style="vertical-align: middle;"
src="cid:part4.88FBE0B3.BFD3565A@mercer.edu">.</p>
<p>2. For both terms find the value of <img alt="$x$"
style="vertical-align: middle;"
src="cid:part1.8E42435D.18A7294B@mercer.edu"> that makes the
entire expression in parenthesis equal to zero. In this case it
would be <img alt="$x=0.25$" style="vertical-align: middle;"
src="cid:part6.896ABAB4.89C4020B@mercer.edu"> and <img
alt="$x=0.5$" style="vertical-align: middle;"
src="cid:part7.D2698952.4A234D21@mercer.edu"></p>
<p>3. Whichever one of these is SMALLER is your upper bound. In
this case that is $x=0.25}.</p>
<p><br>
</p>
<p>Once you set the initial bounds you then have to set an initial
value for x. ANY NUMBER between 0 and the upper bound should work
there. In this particular example you could probably leave it at
zero - or you could set it to 0.1 which is what I would do.</p>
<p><br>
</p>
<p>
<blockquote type="cite">I don’t get the the thought process behind
determining what the bound is. Especially when a number can’t
cleanly multiply to equal zero. For example the latest quiz had
in the law of mass action, for the reactants, it’s ((2-3x)^2). I
couldn’t find a clear number that would result in 2-2=0, so I
did trial and error and I got lucky. Can you think out loud for
me? Surely there’s more to it than that. </blockquote>
</p>
<p>Hopefully my comments above helped with this. In the case of an
expression like:</p>
<p><img alt="$(2-3x)$" style="vertical-align: middle;"
src="cid:part8.1BE765FD.4C74679B@mercer.edu"> <br>
</p>
<p>think about doing the following...</p>
<p><img alt="$2-3x=0$" style="vertical-align: middle;"
src="cid:part9.55FB9DF4.31B52B67@mercer.edu"></p>
<p><img alt="$2=3x$" style="vertical-align: middle;"
src="cid:part10.3AEF1915.A188B5CD@mercer.edu"></p>
<p><img alt="$x=\frac{2}{3}$" style="vertical-align: middle;"
src="cid:part11.674E7960.35298413@mercer.edu"></p>
<p>That should work every time if the rest of your expression is set
up correctly in solver.</p>
<p>As always - keep asking if you are confused.</p>
<p><br>
</p>
<pre class="moz-signature" cols="72">--
Andrew J. Pounds, Ph.D. (<a class="moz-txt-link-abbreviated" href="mailto:pounds_aj@mercer.edu">pounds_aj@mercer.edu</a>)
Professor of Chemistry and Computer Science
Director of the Computational Science Program
Mercer University, Macon, GA 31207 (478) 301-5627
</pre>
</body>
</html>