Sujet: sums liste de sujets
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	Odds and evens in an n by n+1 table		2010-01-21
		Shankar pose la question : The boxes of an n * (n+1) table ( n rows and n+1 columns) are filled with integers. Prove that one can cross out several columns ( not all of them !) so that after this operation all the sums of the numbers in each row will be even. Robert Dawson lui répond.
	The distribution of sample sums		2008-11-21
		Mark pose la question : For large samples, the sample sum (Σ x) has an approximately normal distribution. The mean of the sample sum is n*μ and standard deviation is (σ*√n). The distribution of savings per account for savings and loan institution has a mean equal to $750 and a standard deviation equal to $25. For a sample of 50 such accounts, find the probability that the sum in the 50 accounts exceeds $38,000. Penny Nom lui répond.
	T-totals		2007-09-26
		Asma pose la question : I wanted to know what i should include in my T-totals maths coursework and also how i should lay out the coursework? Penny Nom lui répond.
	Two groups that have equal sums		2005-09-30
		Anita pose la question : using the numbers 1, 2, 3, 4, 5, 6, 7,and 8. how do we divide them into two groups so that they have equal sums? Penny lui répond.
	Adding consecutive integers		2005-05-13
		Yas pose la question : i need some help with my work which is to investigating sums of consecutive numbers for example: 15= 4+5+6 and 15=1+2+3+4+5 Penny Nom lui répond.
	Two matrix problems		2005-03-30
		Sue pose la question : Question 1 Suppose all matrices in the equation below are square and invertible. Solve for x . BA-1XB-1 + 2BA + In = 0 (the symbol "0" here denotes the matrix of all 0's in it) Also, A-1 or B-1 is indicating inverse and "In" = for example, A-1 times A I hope you understand the above. I have to show all the steps. Question 2 Suppose we consider the set of all 2x2 matrices along with the operations of matrix addition and multiplication. Do they form a field? Why or why not? I think the answer is no because under multiplication it is not commutative and not all square matrices are invertible. I not positive so I'd like some help. Penny Nom lui répond.
	A matrix construction problem		2005-03-14
		Marcelo pose la question : I want to know if is it possible to solve this problem: I have an empty NxM matrix and I know totals (sum) by rows and totals by column. Is there any algorithm to fill the matrix so that the summary of columns and rows gives the original values I have? Harley Weston lui répond.
	Sums and differences		2004-02-10
		David pose la question : The sum of two whole numbers is 63. The difference between the numbers is 10. Find all the possible pairs. Claude Tardif and Penny Nom lui répond.
	Sums of evens		2002-09-14
		Rosa pose la question : How do I find a geometric way to easily compute sums of consecutive even numbers 2 + 4 + 6 + .... Leeanne Boehm and Harley Weston lui répond.
	A dollar, quarter, dime, nickle and penny		2001-01-07
		Sarah pose la question : Arnold has a dollar coin, one dime, one quarter, one nickel, and a penny. The number of different sums of money that can be formed using three coins is... Penny Nom lui répond.
	Riemann sums		2000-03-30
		Joshua D. Parham pose la question : If n is a positive integer, then lim (1/n)[1/(1+1/n) + 1/(1+(2/n) + ... + 1/(1+n/n)] n->infinity can be expressed as the integral from 1 to 2 of 1/x dx Penny Nom lui répond.

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