Art of Problem Solving

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A user with 247 edits. Account created on 28 October 2009.
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15 January 2013

28 May 2012

  • 14:0714:07, 28 May 2012 diff hist +3,793 N 2006 SMT/Geometry Problems/Problem 4 Created page with "==Problem== The distance <math> AB </math> is <math> l </math>. Find the area of the locus of points <math> X </math> such that <math> 15^\circ\le\angle AXB\le30^\circ </math> an..." current
  • 11:2211:22, 28 May 2012 diff hist +1,363 N 2006 SMT/Geometry Problems/Problem 3 Created page with "==Problem== Circle <math> \gamma </math> is centered at <math> (0, 3) </math> with radius <math> 1 </math>. Circle <math> \delta </math> is externally tangent to circle <math> \g..." current
  • 11:0011:00, 28 May 2012 diff hist +1,991 N 2006 SMT/Geometry Problems/Problem 2 Created page with "==Problem== Given square <math> ABCD </math> of side length <math> 1 </math>, with <math> E </math> on <math> \overline{CD} </math> and <math> F </math> in the interior of the sq..." current
  • 10:3810:38, 28 May 2012 diff hist +1,860 N 2006 SMT/Geometry Problems/Problem 1 Created page with "==Problem== Given a cube, determine the ratio of the volume of the octahedron formed by connecting the centers of each face of the cube to the volume of the cube. ==Solution== ..." current
  • 09:3509:35, 28 May 2012 diff hist +703 N 2006 SMT/Algebra Problems/Problem 10 Created page with "==Problem== Evaluate: <math> \sum_{k=1}^{\infty}\frac{k}{a^{k-1}} </math> for all <math> |a|<1 </math>. ==Solution== Let <math> S=\sum_{k=1}^{\infty}\frac{k}{a^{k-1}}=\frac{1}{a..." current
  • 09:3009:30, 28 May 2012 diff hist +1,131 N 2006 SMT/Algebra Problems/Problem 9 Created page with "==Problem== Principal Skinner is thinking of two integers <math> m </math> and <math> n </math> and bets Superintendent Chalmers that he will not be able to determine these integ..." current
  • 08:5208:52, 28 May 2012 diff hist +1,306 N 2006 SMT/Algebra Problems/Problem 8 Created page with "==Problem== Evaluate: <cmath> \sum_{x=2}^{10}\frac{2}{x(x^2-1)}. </cmath> ==Solution== Since the denominator of the fraction is factorable, we try partial fraction decompositio..." current
  • 08:4008:40, 28 May 2012 diff hist +802 N 2006 SMT/Algebra Problems/Problem 7 Created page with "==Problem== Find all solutions to <math> aabb=n^4-6n^3 </math>, where <math> a </math> and <math> b </math> are nonzero digits, and <math> n </math> is an integer. (<math> a </ma..." current
  • 08:3108:31, 28 May 2012 diff hist +1,360 N 2006 SMT/Algebra Problems/Problem 6 Created page with "==Problem== Let <math> a, b, c </math> be real numbers satisfying: <cmath> ab-a=b+119 </cmath> <cmath> bc-b=c+59 </cmath> <cmath> ca-c=a+71 </cmath> Determine all possible valu..."
  • 08:0308:03, 28 May 2012 diff hist +1,778 N 2006 SMT/Algebra Problems/Problem 5 Created page with "==Problem== Jerry is bored one day, so he makes an array of Cocoa pebbles. He makes <math> 8 </math> equal rows with the pebbles remaining in a box. When Kramer drops by and eats..." current
  • 07:5507:55, 28 May 2012 diff hist +1,250 N 2006 SMT/Algebra Problems/Problem 4 Created page with "==Problem== Simplify: <math> \frac{a^3}{(a-b)(a-c)}+\frac{b^3}{(b-a)(b-c)}+\frac{c^3}{(c-a)(c-b)} </math> ==Solution== Firstly, we notice that the factors in the denominators ar..." current
  • 07:4307:43, 28 May 2012 diff hist +1,313 N 2006 SMT/Algebra Problems/Problem 3 Created page with "==Problem== A Gaussian prime is a Gaussian integer <math> z=a+bi </math> (where <math> a </math> and <math> b </math> are integers) with no Guassian integer factors of smaller ab..." current
  • 07:3107:31, 28 May 2012 diff hist +1,291 N 2006 SMT/Algebra Problems/Problem 2 Created page with "==Problem== Find the minimum value of <math> 2x^2+2y^2+5z^2-2xy-4yz-4x-2z+15 </math> for real numbers <math> x, y, z </math>. ==Solution== ===Solution 1=== Notice that <math> 2x..." current
  • 07:0107:01, 28 May 2012 diff hist +1,399 N 2006 SMT/Algebra Problems/Problem 1 Created page with "==Problem== A finite sequence of positive integers <math> m_i </math> for <math> i=1, 2, \cdots, 2006 </math> are defined so that <math> m_1=1 </math> and <math> m_i=10m_{i-1}+1 ..." current

27 May 2012

26 May 2012

  • 21:5821:58, 26 May 2012 diff hist +1,079 N 1974 AHSME Problems/Problem 29 Created page with "==Problem== For <math> p=1, 2, \cdots, 10 </math> let <math> S_p </math> be the sum of the first <math> 40 </math> terms of the arithmetic progression whose first term is <math> ..."
  • 21:4121:41, 26 May 2012 diff hist +1,728 N 1974 AHSME Problems/Problem 28 Created page with "==Problem== Which of the following is satisfied by all numbers <math> x </math> of the form <cmath> x=\frac{a_1}{3}+\frac{a_2}{3^2}+\cdots+\frac{a_{25}}{3^{25}} </cmath> where ..."
  • 21:3121:31, 26 May 2012 diff hist +770 N 1974 AHSME Problems/Problem 27 Created page with "==Problem== If <math> f(x)=3x+2 </math> for all real <math> x </math>, then the statement: "<math> |f(x)+4|<a </math> whenever <math> |x+2|<b </math> and <math> a>0 </math> and <..."
  • 21:2721:27, 26 May 2012 diff hist +816 N 1974 AHSME Problems/Problem 26 Created page with "==Problem== The number of distinct positive integral divisors of <math> (30)^4 </math> excluding <math> 1 </math> and <math> (30)^4 </math> is <math> \mathrm{(A)\ } 100 \qquad ..."
  • 21:2121:21, 26 May 2012 diff hist +1,510 N 1974 AHSME Problems/Problem 25 Created page with "==Problem== In parallelogram <math> ABCD </math> of the accompanying diagram, line <math> DP </math> is drawn bisecting <math> BC </math> at <math> N </math> and meeting <math> A..."
  • 21:1221:12, 26 May 2012 diff hist +1,109 N 1974 AHSME Problems/Problem 24 Created page with "==Problem== A fair die is rolled six times. The probability of rolling at least a five at least five times is <math> \mathrm{(A)\ } \frac{13}{729} \qquad \mathrm{(B) \ }\frac{1..."
  • 21:0321:03, 26 May 2012 diff hist +2,053 N 1974 AHSME Problems/Problem 23 Created page with "==Problem == In the adjoining figure <math> TP </math> and <math> T'Q </math> are parallel tangents to a circle of radius <math> r </math>, with <math> T </math> and <math> T' </..."
  • 20:3220:32, 26 May 2012 diff hist +1,141 N 1974 AHSME Problems/Problem 22 Created page with "==Problem== The minimum of <math> \sin\frac{A}{2}-\sqrt{3}\cos\frac{A}{2} </math> is attained when <math> A </math> is <math> \mathrm{(A)\ } -180^\circ \qquad \mathrm{(B) \ }60..."
  • 20:1420:14, 26 May 2012 diff hist +1,124 N 1974 AHSME Problems/Problem 21 Created page with "==Problem== In a geometric series of positive terms the difference between the fifth and fourth terms is <math> 576 </math>, and the difference between the second and first terms..."
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