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Arc length |
2002-04-17 |
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Vix pose la question : Find the point on the curve r(t)=(12sint)i-(12cost)j+5tk at a distance 13pi units along the curve from the point (0,-12,0) when t=0 in the direction opposite to the direction of increasing arc length. Harley Weston lui répond. |
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Ratios |
2002-04-17 |
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A student pose la question :
- Medication is givin at 1cc. per 20 pounds of body weight. A dog weighs 16 pounds how many ccs. of medication does the dog get?
- Dr. Lee wants you to prepare 1000 ml. of a 10% dextrose solution in lactaed ringers for diuresis or a patient you have a 1 L bag of lactated ringers and 500 ml of 50% dextrose for injection. How would you prpare the solution?
Penny Nom lui répond. |
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Related rates |
2002-04-17 |
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Molly pose la question : A tanker spilled 30 ft cubed of chemicals into a river, causing a circular slick whose area is expanding while its thickness is decreasing. If the radius of the slick expands at the rate of 1 foot per hour, how fast is them thickness of the slick decreasing when the area is 100 feet squared? Penny Nom lui répond. |
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Un empilement de spheres |
2002-04-16 |
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Sébastien pose la question : Lorsque j'etais encore a l'universite je me souviens qu'un prof nous avez dit, sans le demontrer (ce n'est pas bien du tout de sa part) que l'espace minimal qui existe dans un empilement de spheres est de l'ordre de 26% Voici plusieurs jours que je cherche a resoudre ce probleme de geometrie, et je n'arrive meme pas a trouver comment l'aborder. Claude Tardif lui répond. |
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Two algebra problems |
2002-04-14 |
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Ashley pose la question : Question 1: For all values of a, let < a > be defined as < a > = 4a - 4 . Which of the following equals < 6 > - < 5 >? A: < 2 > B: < 3 > C: < 4 > D: < 5 > E: < 6 > Question 2: If 5n + p = 3 and 2m - 10n = 2, what is the value of m + p? Penny Nom lui répond. |
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A polynomial |
2002-04-14 |
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A student pose la question : A polynomial function is described by the following conditions: f(x) has two real zeros at x= -2 and x= 1, each of multiplicity 2 f(x) has two complex zeros as x goes to -infinity, f(x) goes to +infinity as x goes to +infinity, f(x) goes to +infinity f(x) has a y-intercept at (0,2) Sketch a polynomial function that satisfies the above conditions. Write an equation for function f(x) Write another function g(x) that also satisfies the above parameters. Penny Nom lui répond. |
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How many gallons of water in a cubic foot? |
2002-04-14 |
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Richard pose la question : I am tring to find out how many gallons of water in a cubic foot. Penny Nom lui répond. |
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The vertex of a cone |
2002-04-13 |
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Callie pose la question : Does a cone have a vertex? Penny Nom lui répond. |
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The square root of four |
2002-04-13 |
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Frank pose la question : In a recent quiz we where asked the square root of four. The quizmaster gave the answer as not only 2 but also -2. Being pedantic I queried this. Although -2 squared is 4, does it follow that the root of 4 is -2 Can you enlighten us? Claude Tardif and Penny Nom lui répond. |
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The bleep test |
2002-04-13 |
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Lorraine pose la question : I am currently undergoing training and have asked about a fitness test called the bleep test. The bleep test involves running continuously between two points that are 20m apart. These runs are done in time to a pre-recorded bleep sounds on a pre-recorded audio cassette. The time between the recorded bleeps decrease after each minute. I would like to do my own personal version for training but I have to work out the following before doing this: I need to find out the time in-between the beeps at least for the first level so I can work out the difference for the other levels: The information given to me for the first level is : A 20 meter run at 8.5km/hr (how long would it take?) Please let me know if there is any way in working out this query with the information given. Leeanne Boehm lui répond. |
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Calculate profit |
2002-04-13 |
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Allison pose la question : If I sell something for $75; and my cost is $40, I make $35 profit. How do I calculate the profit percent I made on that transaction? Penny Nom lui répond. |
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Nombres algebriques sur Q |
2002-04-11 |
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Un eleve pose la question : On sait que le corps des nombres algebriques sur Q est algebriquement clos. A priori partant d'un polynome f a coefficients algebriques sur Q on devrait pouvoir un trouver un polynome g a coefficients rationnels dont une partie des racines est constituee de racines du premier. y-at-il un algorithme qui permet qui permet le passage de f a g ? Claude Tardif lui répond. |
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Problème de traduction |
2002-04-11 |
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Philippe pose la question : Je suis professeur de mathématiques en collège et j'aimerai que la classe de 5ème, qui a une spécialité "Anglais", fasse un cours de mathématiques en anglais. N'étant pas moi même trés fort en mathématiques version anglaises, je vous sollicite donc pour répondre à certaines de mes questions. Par exemple, je me demande comment on dit " 3 fois 5" en anglais. "2 plus 2" se dit "2 and 2 is...". J'ai des problèmes avec la multiplication, la soustraction (" minus" ou "out of" ?), et la division. De même , comment dit-on "2/3". J'ai aussi des problèmes pour le vocabulaire mais je pense pouvoir le résoudre en utilisant un bon dictionnaire. Ma question est donc: Existe-t-il des sites qui propose ce genre de traduction? Claude Tardif lui répond. |
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Diagonals in a polygon |
2002-04-10 |
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Murray pose la question : If you have a regular polygon with n sides and you draw all (n-3)n/2 diagonals how many intersection will they form with each other and how many sections will they devide the polygon into. Caude Tardif and Chris Fisher lui répond. |
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n +1, n+2, n+3, and n+4 are all composite |
2002-04-09 |
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Jonathan pose la question : Find the small integer n such that n +1, n+2, n+3, and n+4 are all composite Penny Nom lui répond. |
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