Wikipedia:Reference desk/Archives/Mathematics/January 2009

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January 1

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 1

1. Simple permutations/combinations?

January 2

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 2

1. Modular arithmetic into which the primes fit neatly

January 3

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 3

1. Fractal line
2. What is the expected value of the lowest of four numbers?
3. lease money factor

January 4

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 4

1. Sir Isaac Newton

January 5

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 5

1. Discussion for On-Line Algebra

January 6

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 6

1. Product (not normal) symbol in LaTeX
2. does 0.999... equal 1 ?
3. max size of disconnected graph
4. roots of y=0 and definitions
5. Determining size of label for cylindrical bottle

January 7

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 7

1. Estimation problem

January 8

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 8

1. Group Axioms
2. Original research and WP:OR
3. Seeking a definition of "Positive Terms"
4. Question relating to the discriminant

January 9

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 9

1. a question regarding liters and milliliters
2. Is this equation solveable without a computer/brute force?
3. Algebra II word problem

January 10

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 10

1. Does this continued fraction converge?
2. Pentagons
3. max size of a k-component graph
4. Multiplying integers by digit-swapping.
5. 3x3 Antisymmetric Matrices
6. Three '2's Problem

January 11

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 11

1. Group of points on the unit sphere
2. Unidentified trig functions/identities?
3. Conic section slope of directrix
4. Cubic functions
5. Manifolds

January 12

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 12

1. A Pascal's triangle question I've never seen before
2. Leibniz notation
3. Lebesgue Integrals
4. [[Wikipedia:Reference_desk/Archives/Mathematics/2009 January 12#e^i<.2Fsup>|eⁱ]]
5. combination and permutation
6. Law of excluded middle

January 13

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 13

1. the complex plane
2. is a straight line a right angle triangle?
3. Lefschetz numbers
4. Interest calculation (discontinuous)
5. Convolution

January 14

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 14

1. Sphere specialists?
2. Modeling using overlapping probability distributions
3. definition for geometry situation

January 15

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 15

1. Trivial questions and removal of posts
2. Interesting geometric and probability question

January 16

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 16

1. Probability and the universe
2. If a coefficient is significantly different from 1.00
3. Arclength
4. Matrix
5. Basic math elements
6. Measureable sets
7. check

January 17

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 17

1. Exam on Wednesday! Help me!
2. category has fibre products => has equalisers?
3. Spider pursuing a fly on the net of a polyhedron
4. Balls

January 18

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 18

1. 3 spiders and a fly
2. volume of a nonEuclidean tetrahedron
3. Infinity multiplied by zero
4. [[Wikipedia:Reference_desk/Archives/Mathematics/2009 January 18#the square root of $i<.2Fmath>|thesquarerootof<math>i$]]
5. Henge circles
6. Continued fractions and quadratic irrationals
7. One cannot reconstruct a finite group from its character table

January 19

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 19

1. math coincidence
2. Level in a horizontal cylinder
3. Meaning of 'deviated from their sample means'
4. A question about consistent mass matrices in Finite Element Analysis

January 20

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 20

1. Geometry problem
2. Ordinary Annuity
3. Positive roots of subsystems

January 21

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 21

1. solving for radius?
2. Diophantine
3. [[Wikipedia:Reference_desk/Archives/Mathematics/2009 January 21#Integrals ∫_{a<.2Fsub>∏f(xn<.2Fsub>)dxn<.2Fsub>|Integrals ∫a∏f(xn)dxn]]}
4. What do you call a + or - sign (to indicate positive or negative numbers)?
5. Math, via Civil Engineering
6. Transcentdental numbers

January 22

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 22

1. about infinity
2. Physics: power of water pump
3. Commuting elements in SO(3)
4. Physics: Work from force on inclined plane
5. Compound compound Poisson Distribution
6. Generalised Gauss-Bonnet theorem

January 23

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 23

1. logical numerical order to follow
2. circles

January 24

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 24

1. would you give credit?
2. why is mathematics a requirement
3. Alternative inequality symbols and logic

January 25

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 25

1. Riemann Surface for Dummies
2. simple quadrilateral from distance matrix
3. Unity
4. Question about probability and ergodicity

January 26

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 26

1. Turkish numerals
2. zero divisors in non-commutative rings
3. electric watts to amps
4. [[Wikipedia:Reference_desk/Archives/Mathematics/2009 January 26#What is $frac{0}{0}<.2Fmath>?|Whatis<math>frac{0}{0}$?]]
5. [[Wikipedia:Reference_desk/Archives/Mathematics/2009 January 26#What is 0^{0<.2Fsup>?|What is 00?]]}
6. Variable Changing in Multiple Integrals
7. Definition for │x│
8. Many-body problems
9. Roman numerals on watch dials
10. Lim sup of number of divisors
11. Notation

January 27

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 27

1. Rotating a Right Traingle 180 Degrees
2. Weierstrass-Enneper parametrization
3. College Math Help!
4. why not fermats last conjecture
5. Wake Angle
6. Co-ordinate geometry
7. saving time
8. Evaluate trigonometric definite integral

January 28

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 28

1. Notation used in Wikipedia article "Prime Gap"

January 29

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 29

1. Proven but not constructed
2. Some Number Theory
3. Sum of interior angles of polygons constant - proof?
4. Numerical error
5. sin(G)

January 30

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 30

1. Calc 1 Question
2. Common name for spheres and circles.
3. Rotation along a certain point...
4. Curiosity has revived the calculus - A math homework from yesteryear

January 31

Wikipedia:Reference_desk/Archives/Mathematics/2009 January 31

1. formula to calculate pi
2. Euler's proof that god exists
3. Localization Morphism
4. elementary graph theory
5. Modular arithmetic/number theory
6. Vectors & Potentials