This commit is contained in:
2014-05-31 22:03:30 +04:00
parent 8d2c079900
commit 1c1c6fe543
871 changed files with 50851 additions and 0 deletions

78
ProjectEuler/pe/p285.html Normal file
View File

@@ -0,0 +1,78 @@
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="author" content="Colin Hughes" />
<meta name="description" content="A website dedicated to the fascinating world of mathematics and programming" />
<meta name="keywords" content="programming,mathematics,problems,puzzles" />
<title>Problem 285 - Project Euler</title>
<link rel="shortcut icon" href="http://projecteuler.net/favicon.ico" />
<link rel="stylesheet" type="text/css" href="style_main.css" />
<link rel="stylesheet" type="text/css" href="style_light.css" />
<script type="text/x-mathjax-config">
MathJax.Hub.Config({
jax: ["input/TeX", "output/HTML-CSS"],
tex2jax: {
inlineMath: [ ["$","$"], ["\\(","\\)"] ],
displayMath: [ ["$$","$$"], ["\\[","\\]"] ],
processEscapes: true
},
"HTML-CSS": { availableFonts: ["TeX"] }
});
</script>
<script type="text/javascript" src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS_HTML">
</script>
</head>
<body>
<div id="container">
<div id="nav" class="noprint">
<ul>
<li><a href="about" title="About" accesskey="h">About</a></li>
<li><a href="register" title="Register" accesskey="1">Register</a></li>
<li id="current"><a href="problems" title="Problems" accesskey="2">Problems</a></li>
<li><a href="login" title="Login" accesskey="3">Login</a></li>
</ul>
</div>
<div id="info_panel"><a href="rss2_euler.xml"><img src="images/icon_rss.png" alt="RSS Feed" title="RSS Feed" /></a><a href="secure=528a0"><img src="images/icon_lock.png" alt="Use secure connection" title="Use secure connection" /></a></div>
<div id="logo" class="noprint">
<img src="images/pe_banner_light.png" alt="Project Euler .net" />
</div>
<div id="content">
<div style="text-align:center;" class="print"><img src="images/pe_banner.png" alt="projecteuler.net" style="border:none;" /></div>
<h2>Pythagorean odds</h2><div class="info" style="cursor:help;width:200px;margin-bottom:10px;"><h3>Problem 285</h3><span style="width:300px;color:#666;">Published on Saturday, 3rd April 2010, 05:00 am; Solved by 685</span></div>
<div class="problem_content" role="problem">
<p>Albert chooses a positive integer <var>k</var>, then two real numbers <var>a</var>, <var>b</var> are randomly chosen in the interval [0,1] with uniform distribution.<br />
The square root of the sum (<var>k</var>&middot;<var>a</var>+1)<sup>2</sup>&thinsp;+&thinsp;(<var>k</var>&middot;<var>b</var>+1)<sup>2</sup> is then computed and rounded to the nearest integer. If the result is equal to <var>k</var>, he scores <var>k</var> points; otherwise he scores nothing.</p>
<p>For example, if <var>k</var>&thinsp;=&thinsp;6, <var>a</var>&thinsp;=&thinsp;0.2 and <var>b</var>&thinsp;=&thinsp;0.85, then (<var>k</var>&middot;<var>a</var>+1)<sup>2</sup>&thinsp;+&thinsp;(<var>k</var>&middot;<var>b</var>+1)<sup>2</sup>&thinsp;=&thinsp;42.05.<br />
The square root of 42.05 is 6.484... and when rounded to the nearest integer, it becomes 6.<br />
This is equal to <var>k</var>, so he scores 6 points.</p>
<p>It can be shown that if he plays 10 turns with <var>k</var>&thinsp;=&thinsp;1, <var>k</var>&thinsp;=&thinsp;2, ..., <var>k</var>&thinsp;=&thinsp;10, the expected value of his total score, rounded to five decimal places, is 10.20914.</p>
<p>If he plays 10<sup>5</sup> turns with <var>k</var>&thinsp;=&thinsp;1, <var>k</var>&thinsp;=&thinsp;2, <var>k</var>&thinsp;=&thinsp;3, ..., <var>k</var>&thinsp;=&thinsp;10<sup>5</sup>, what is the expected value of his total score, rounded to five decimal places?</p>
</div><br />
<br /></div>
<div id="footer" class="noprint">
<a href="copyright">Project Euler Copyright Information</a>
<!--/Creative Commons License--><!-- <rdf:RDF xmlns="http://web.resource.org/cc/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#">
<Work rdf:about="">
<license rdf:resource="http://creativecommons.org/licenses/by-nc-sa/2.0/uk/" />
<dc:type rdf:resource="http://purl.org/dc/dcmitype/Text" />
</Work>
<License rdf:about="http://creativecommons.org/licenses/by-nc-sa/2.0/uk/"><permits rdf:resource="http://web.resource.org/cc/Reproduction"/><permits rdf:resource="http://web.resource.org/cc/Distribution"/><requires rdf:resource="http://web.resource.org/cc/Notice"/><requires rdf:resource="http://web.resource.org/cc/Attribution"/><prohibits rdf:resource="http://web.resource.org/cc/CommercialUse"/><permits rdf:resource="http://web.resource.org/cc/DerivativeWorks"/><requires rdf:resource="http://web.resource.org/cc/ShareAlike"/></License></rdf:RDF> -->
</div>
</div>
<div style="height:1px;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </div></body>
</html>