.
. centre de ressources dilemmes et doutes le visage humain de mathématiques Qui sommes-nous Problème de mois activités de promotion babillard
Centrale des maths - centraledesmaths.uregina.ca
Dilemmes & doutes
« D & D »
. .
Fresh off the press   Voici les articles les plus récents
de notre base de données:
. .
nouvelle recherche

 
Page
781/886
Odd plus even is odd 2001-10-14
James pose la question :
Why is the sum of an odd number and an even number always odd?
Peny Nom lui répond.
Area of a quilt 2001-10-14
Jack pose la question :
  1. how would you find the area of the quilt? which is a square

  2. how would you fined the area of each square?

Penny Nom lui répond.
Theme day 2001-10-14
A teacher pose la question :
I woulld like a math theme for a theme day in a high school, grades 9-12. Our last theme was fractal fest.
Penny Nom and Claude Tardif lui répond.
Maximize the area 2001-10-13
Mike pose la question :

I have no clue how to do this problem. Here is what the professor gave to us:

A=LW

C=E(2L+2W) + I(PL)

Where P = # of partitions

E= cost of exterior of fence

I = cost of interior of fence

C = total cost of fence

.
.
.

Harley Weston lui répond.
Mathematical & conventional meaning of a word 2001-10-12
A student pose la question :
What is the mathematical & conventional meaning of a word? Like the word Rational or Median.
Penny Nom lui répond.
60 seconds in a minute 2001-10-11
Andy pose la question :
I am a fourth grade teacher. Yesterday my students asked "Why are there 60 seconds in a minute?" Which also led to 60 minutes in an hour? I have had trouble determining why the number 60? Any help would be appreciated.
Penny Nom lui répond.
4 sinx cosy = 1 2001-10-10
A student pose la question :
How would i differentiate the following example in terms of t (x and y are functions of t)

4 sinx cosy = 1


Claude Tardif lui répond.
Acres 2001-10-10
Allison pose la question :
how many feet are there in an acre?
Chris Fisher lui répond.
eix = cosx + isinx 2001-10-10
Peter pose la question :
Given: eix = cosx + isinx
  1. substitute -x for x to find e-ix, simplifying your answer

  2. use the given and part a to find an identity for cosx making no reference to trig functions

  3. find an identity for sinx
  4. .
  5. .

Penny Nom lui répond.
When will the ship disappear? 2001-10-10
Stacy pose la question :
If the sail of a ship were a 100 ft. tall and you were a mouse at the edge of the shore looking out at it, how far out would the ship be when it disappears? ( your eye level is level with the water.)
Harley Weston lui répond.
Ratio and proportion 2001-10-10
Steve pose la question :
Where would you use a proportion and/or a ratio in a real life job or problem.
Leeanne Boehm and Walter Whiteley lui répond.
Six nines 2001-10-09
A mom pose la question :
My middle schooler (sixth) has to calculate the integers 0-20 using only 6 nines. We have done all but the integer 14. He can not use decimals or double the nine like 99 or 19. the fraction 9/9 is okay. Keep in mind of course the order of operations.
Claude Tardif lui répond.
Pythagoras & magic squares 2001-10-09
John pose la question :
My grandson became intrigued when he recently 'did' Pythagoras at elementary school. He was particularly interested in the 3-4-5 triangle, and the fact that his teacher told him there was also a 5-12-13 triangle, i.e. both right-angled triangles with whole numbers for all three sides. He noticed that the shortest sides in the two triangles were consecutive odd numbers, 3 & 5, and he asked me if other right angled triangles existed, perhaps 'built' on 7, 9, 11 and so on.

I didn't know where to start on this, but, after trying all sorts of ideas, we discovered that the centre number in a 3-order 'magic square' was 5, i.e. (1+9)/2, and that 4 was 'one less'. Since the centre number in a 5-order 'magic square' was 13 and that 12 was 'one less' he reckoned that he should test whether a 7-order square would also generate a right-angled triangle for him. He found that 7-24-25, arrived at by the above process, also worked! He tried a few more at random, and they all worked. He then asked me two questions I can't begin to answer ...

  1. Is there a right-angled triangle whose sides are whole numbers for every triangle whose shortest side is a whole odd number? and

  2. Is each triangle unique (or, as he put it, can you only have one whole-number-sided right-angled triangle for each triangle whose shortest side is an odd number)?

Chris Fisher lui répond.
Lucas' theorem 2001-10-09
Tania pose la question :
How could I demonstrate: nCp is congruent to floor(n/p) (modulo p)? where rCk is a binomial coefficient, rCk = r(r-1)...(r-k+1)/k(k-1)...1, and p is a prime number
Richard McIntosh lui répond.
Binomial probabilities 2001-10-08
Amna pose la question :
I had a few binomial probability questions which I can not use from the tables as instructed:
  1. If 60 % of television viewers are watching a certain program, what is the probability tha tmore than half of those selected in a random sample of five will be watching the specified program?

  2. If it is known according to Mendel's Law, that we can expect in teh long run to have 3 white, 1 brown rabbits in every 4 rabbits of a certain type, what is the probability that 2 in a litter of 3 will be white?

  3. On the average, 2% of the items sold in a department store are returned for refunds. what is the probability that of its next five items sold, at most two will be returned for refunds?

Leeanne Boehm lui répond.
 
Page
781/886

 

 


Centrale des maths reçoit une aide financière de l’Université de Regina et de The Pacific Institute for the Mathematical Sciences.

CMS
.

 

accueil centre de ressources accueil Société mathématique du Canada l'Université de Regina PIMS