Difference between revisions of "User:Temperal/The Problem Solver's Resource8"

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==<span style="font-size:20px; color: blue;">Geometry</span>==
|+ <span style="background:aqua; border:1px solid black; opacity: 0.6;font-size:30px;position:relative;bottom:8px;border-width: 5px;border-color:blue;border-style: groove;position:absolute;top:50px;right:155px;width:820px;height:40px;padding:5px;">The Problem Solver's Resource</span>
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This is the geometry page. Of course, there is much too much to cover here, but this will review the basics.
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==<span style="font-size:20px; color: blue;">Intermediate Number Theory</span>==
 
These are more complex number theory theorems that may turn up on the USAMO or Pre-Olympiad tests.
 
This will also cover diverging and converging series, and other such calculus-related topics.
 
 
 
===General Mean Inequality===
 
 
 
Take a set of functions <math>m_j(a) = \left({\frac{\sum a_i^j}{n}}\right)^{1/j}</math>.
 
 
 
Note that <math>m_0</math> does not exist. The geometric mean is <math>m_0 = \lim_{k \to 0} m_k</math>.
 
For non-negative real numbers <math>a_1,a_2,\ldots,a_n</math>, the following holds:
 
 
 
<math>m_x \le m_y</math> for reals <math>x<y</math>.
 
 
 
I<math>m_2</math> is the quadratic mean, <math>m_1</math> is the arithmetic mean, <math>m_0</math> the geometric mean, and <math>m_{-1}</math> the harmonic mean.
 
 
 
===Chebyshev's Inequality===
 
 
 
Given real numbers <math>a_1 \ge a_2 \ge ... \ge a_n \ge 0</math> and <math>b_1 \ge b_2 \ge ... \ge b_n</math>, we have
 
 
 
%{\frac{\sum a_ib_i}{n}} \ge {\frac{\sum a_i}{n}}{\frac{\sum b_i}{n}}%.
 
 
 
===Minkowsky's Inequality===
 
 
 
Given real numbers <math>a_1,a_2,...,a_n</math> and <math>b_1,b_2,\ldots,b_n</math>, the following holds:
 
 
 
<math>\sqrt{\sum a_i^2} + \sqrt{\sum b_i^2} \ge \sqrt{\sum (a_i+b_i)^2}</math>
 
 
 
===Nesbitt's Inequality===
 
 
 
For all positive real numbers <math>a</math>, <math>b</math> and <math>c</math>, the following holds:
 
 
 
<math>{\frac{a}{b+c}} + {\frac{b}{c+a}} + {\frac{c}{a+b}} \ge {\frac{3}{2}}</math>.
 
 
 
===Schur's inequality===
 
 
 
Given positive real numbers <math>a,b,c</math> and real <math>r</math>, the following holds:
 
 
 
<math>a^r(a-b)(a-c)+b^r(b-a)(b-c)+c^r(c-a)(c-b)\ge 0</math>.
 
 
 
===Fermat-Euler Identitity===
 
If <math>gcd(a,m)=1</math>, then <math>a^{\phi{m}}\equiv1\pmod{m}</math>, where <math>\phi{m}</math> is the number of relitvely prime  numbers lower than <math>m</math>.
 
 
 
===Gauss's Theorem===
 
If <math>a|bc</math> and <math>(a,b) = 1</math>, then <math>a|c</math>.
 
 
 
===Power Mean Inequality===
 
For a real number <math>k</math> and positive real numbers <math>a_1, a_2, ..., a_n</math>, the <math>k</math>th power mean of the <math>a_i</math> is
 
 
 
<math>M(k) = \left( \frac{\sum_{i=1}^n a_{i}^k}{n} \right) ^ {\frac{1}{k}}</math>
 
when <math>k \neq 0</math> and is given by the geometric mean]] of the
 
<math>a_i</math> when <math>k = 0</math>.
 
 
 
===Diverging-Converging Theorem===
 
A series <math>\displaystyle_{i=0}^{\infty}S_i</math> converges iff <math>\displaystyle\lim S_i=0</math>.
 
 
 
===Errata===
 
All quadratic residues are <math>0</math> or <math>1\pmod{4}</math>and  <math>0</math>, <math>1</math>, or <math>4</math> <math>\pmod{8}</math>.
 
  
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This will be completed later.
  
 
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Latest revision as of 18:20, 10 January 2009

Introduction | Other Tips and Tricks | Methods of Proof | You are currently viewing page 8.

Geometry

This is the geometry page. Of course, there is much too much to cover here, but this will review the basics.

This will be completed later.

Back to page 7 | Continue to page 9