Wikipedia:Reference desk/Archives/Mathematics/October 2010

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October 1

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 1

1. Transforming 3 points to a new coordinate plane in 3D Cartesian space
2. Poincaré-Hopf Theorem
3. basic combinatorics
4. using CAS to find the catenary parameter a that will give us a curve that will pass through a given point

October 2

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 2

1. more combinatorics
2. Second moment of the binomial distribution
3. More Limits

October 3

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 3

1. k = x + 1/x
2. Writing a puzzle
3. Continued Fraction Factorisation Method - What is the point?

October 4

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 4

1. Name the object
2. Generalized Metric Space

October 5

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 5

1. Trying to find a recent question in the archives
2. Probability: number of die throws necessary to reach a certain probability of covering all numbers
3. Truncated lognormal
4. Probability

October 6

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 6

1. combinatorial identity
2. Stuck trying to prove a division problem
3. include or not to include
4. Optimal strategy for coin flipping game
5. Set theory notation
6. Minimal domain hash function
7. Complete theory with a finite number of countable models

October 7

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 7

1. More general form (and an image) for sine's continued fraction.
2. binomial coeffcient
3. hexagon torus
4. Quick group theory question

October 8

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 8

1. (1+z)/(1+conj(z))=z
2. Asymptotic Distribution
3. is this a true statement
4. where is the difficulty?
5. Principle of inclusion/exclusion
6. Is there a strictly analytic way of solving complex number simplification problems?
7. Taylor and MacLaurin series

October 9

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 9

1. angle trisection
2. Second Step Analysis for Markov Chains
3. Biostatistics / math question
4. Slope of a linear equation
5. Probability

October 10

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 10

1. Intersection of 2 dense subspaces of a normed vector space necessarily dense?
2. Very straightforward probability
3. A mirror problem

October 11

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 11

1. Markov Chains
2. Understanding the Double Dual
3. Reverse Fourier
4. Map from free abelian group onto the integers

October 12

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 12

1. Rings with infinite height
2. A simple exponentiation math problem

October 13

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 13

1. a paradox?
2. Laplace transform of a matrix?

October 14

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 14

1. direction relative velocity

October 15

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 15

1. Division by zero
2. Variance
3. Vector Fields and the Indices
4. Coefficients in lengthy expansions
5. could you explain cayley graph

October 16

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 16

1. 1/n in base b
2. Factorise this polynomial....
3. Posterior distribution of lambda
4. Series of bounded functions
5. Improper Integral
6. Final coordinate
7. connect the opposite sides of a square with lines that don't cross

October 17

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 17

1. human values

October 18

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 18

1. Displacement –> Velocity
2. trouble with differentiating something using only first principles
3. Statistics
4. how to refute someone's life work nicely
5. The limit of sin x
6. Combinatorics
7. Test guessing Probability

October 19

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 19

1. Quick query on field extension K-homomorphisms and isomorphisms
2. More complex number trigonometry
3. related to the question above
4. Rectification
5. how does arXiv work, or help with peer review?

October 20

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 20

1. floor( exponential random variable ) = geometric distribution

October 21

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 21

1. Formula for converting solid volume to liquid volume
2. Bachmuth representation
3. What is Mathematica doing?
4. what do we know about large primes?

October 22

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 22

1. Polynomial degree vs order
2. typesetting a long stream of numbers in Latex?
3. if you had to brute-force a number but could be told some of the digits
4. Quotients
5. Scenario: Traveling to Pandora as seen in James Cameron's movie Avatar
6. Generalization of ordinals
7. Shoelace formula
8. Reducing Transformation Arrays
9. GMAT scoring system
10. Logic - deduction of axioms

October 23

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 23

1. the four-color theorem doesn't seem right to me
2. Help me impress my friend?
3. secure hash
4. terminology
5. can you find an n-digit prime?

October 24

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 24

1. Differentiate a function
2. Finite subgroups of the multiplication group of the unit quaternions
3. Does the position of the median change if a plot is distorted like this?
4. Venn Diagram Word Problems
5. Problem
6. Choosing a pineapple at a supermarket

October 25

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 25

1. Roulette
2. Mentally generating random numbers
3. complete the sequence
4. Ergodicity

October 26

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 26

1. Monomial Ordering
2. Averaging points on a sphere
3. prove that a + b will have the same value as b + a
4. Linear transformation (map) problem, shortcut?
5. physical constants as reported in Wikipedia

October 27

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 27

1. Primitive roots modulo 5^n
2. Standard error and standard deviation
3. 1 = -1 ?
4. how high do cryptographic functions scale (how big primes can you pick?)
5. finding angles in 3D figures
6. Clustering algorithm

October 28

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 28

1. Obscure 3D shape that folds
2. Another Logic query - uncountability
3. Integral calculus
4. Tough probability question
5. Pairs of antihomologous points lie on a circle
6. Fox calculus on [F', F']
7. Differential equation
8. property of primes

October 29

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 29

1. binomial identity
2. chance to win lotto in 70 years
3. Endomorphisms of finite cyclic groups
4. Normal subgroups of prime index
5. getting the first four of the LAST 5 digits? 1234 from 12349
6. what guarantee is there that numbers aren't very easy to factor (o(n))
7. Conjecture

October 30

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 30

1. Divisor of a Mersenne prime
2. The mathematical spontaneity of coffee stirrers
3. Algorithm for next term in series

October 31

Wikipedia:Reference_desk/Archives/Mathematics/2010 October 31

1. Pumping Lemma
2. Analytic injective functions on the extended complex plane
3. Lie Groups and Infinitesimal Actions
4. Incorrectly named theorems