







Les dérivées partielles 
20120516 

Haddouche pose la question : Bonjour,
Je vous demande de bien vouloir m'éclaircir comment on calcule les dérivées partielles généralement étudiées dans les modèles de la concurrence fiscale à titre d'exemple celui de Wildasin ""NASH EQUILIBRIA IN MODELS OF TAX COMPETITION "", dont j'ai essayé toutes les méthodes et aucune d'elle n'est arrivée à trouver le résultat des dérivées de ce dérnier papier, à cet effet, je vous serais reconnaissant de m'éclaicir la méthode afin de résoudre ce problème qui pour moi un vrai mistère à percer.
Je vous remercie infiniment à l'avance.
Et comptant sur votre compréhension, mes salutations les meilleures.
HA Claude Tardif lui répond. 





le prix de départ 
20060910 

un élève pose la question : Une jupe coûte 36 euros après une démarque de 20% quel est le prix de départ moi j'ai trouvé 45 euros mais je n'ai pas la formule de calcul exacte Claude Tardif lui répond. 





Partages inégaux 
20050929 

Un eleve pose la question : Alex et julie ont ensemble 4728 . euro Si Alex donne 538. euro à Julie, ce dernier aurait alors le triple de Julie. Quelle est la somme possédée de chacun? Claude Tardif lui répond. 





Point de partage 
20000221 

Sebastian Murciano pose la question : J'aurais besoin de savoir où je peux trouver de l'informations, ou estce que vous pouvez me donner de l'information sur : Point de partage d'un segment étudié en Secondaire 4. Claude Tardif lui répond. 





Derivées partielle 
19991019 

Arnaud Flandin pose la question : Quel est la definition des derivées partielle Claude Tardif lui répond. 





Partitions of a set 
20191221 

Ghani pose la question : 1. Are set partition "sets"?
2. If they are so then, why are both {{a}{b,c}} and {{a,b}{c}} said to be valid partitions of A ={a,b,c}
despite them having different elements?
(I understand that set are equal if they have the exact same elements).
Thank you! Harley Weston lui répond. 





The divisors (aliquot parts) of a positive integer 
20191031 

Kenneth pose la question : Is there a fast and simple method that can be used to determine the aliquot parts, whole, positive numbers that can divide into another whole, positive number? Harley Weston lui répond. 





One part in 10^x 
20190626 

Jim pose la question : What is the meaning of the phrase ‘one part in 10x” where the x is an exponent? I have seen these examples: “...better than one part in 10x” and “...to within one part in 10x.” Penny Nom lui répond. 





Margin with commission as part of selling price 
20190213 

Anni pose la question : I need to find selling price to put us at 24% margin.
15% commission is based on selling price and is included in our cost.
I'm trying to do it excel and keep getting a circular reference.
Total cost= cost + commission (15% of selling price)
Selling price=total cost + 24% margin Penny Nom lui répond. 





Heat equation 
20171123 

Max pose la question : What does du\dt=a(triangle)^2u mean. Can it be solved for t. Penny Nom lui répond. 





A road trip word problem 
20160410 

Marc pose la question : While on a road trip I imagined this random word problem. Suppose I start a trip of 75 miles. My initial speed is 75 miles per hour. After every mile traveled I decrease my speed by one mile per hour. After the first mile I decrease my speed to 74 miles per hour and so on for each subsequent mile traveled. How long will it take to complete the 75 mile journey? Penny Nom lui répond. 





10800 sq. ft equal approx what part of an acre? 
20160227 

David pose la question : 10800 sq. ft equal approx what part of an acre Penny Nom lui répond. 





Partitions into distinct parts 
20150919 

Brian pose la question : Looking for a formula where I can type in a number, 17 for example, and using the numbers 1 through 17 (1, 2, 3, 4 etc....), to come up with all possible combinations, when added, that will equal 17. And each number can only be used once. I've tried a few search engines but my computer stares at me blankly and scratches its head :/. Chris Fisher lui répond. 





Three investment partners sharing the profit 
20140222 

Ayatullah pose la question : Hello;
We are three partners and bought a property at 2050000 and sold at 2300000.
Details of investment of the partners
X= 1500000
Y= 400000
Z = 150000
My questions are
1) How could i calculate percentage of investment of each partner?
2) How could i deduct 30% commission from each partner in profit?
3) How could i distribute the profit amongst the partners?
Thanks in advance Penny Nom lui répond. 





Restricted partitions 
20130325 

vidya pose la question : I am having a series of numbers eg.( 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15)
I can take any 5 digits eg(15,10,8,6,5) and it should not repeat and the summation should be any predefined static value . eg(44)
That is (15+10+8+6+5=44) . How many summation series will result 44 ?
My problem is how to find this using a formula or any other simpler automation method is there instead of checking one by one all the combinations.
Plz do help me... Thnks in advance Chris Fisher lui répond. 





A bipartite graph 
20121029 

A student pose la question : Suppose that G be a bipartite graph with maximum degree of k.
Prove that:
1)Exists a Kregular bipartite graph that G be subgraph it(H) Claude Tardif lui répond. 





A tank with an inner walled compartment 
20121012 

don pose la question : I have a tank 20 feet diameter, 19' 8" tall with an inner walled compartment that has a 7' 6" radius arc with in the tank. I need to figure out the volume of the inner area and the volume of the larger area. Harley Weston lui répond. 





The integral of sqrt(x) * ln(x) 
20091012 

Oana pose la question : Hi! Can you tell me please how much is : ∫ (√x * ln x) ? Penny Nom lui répond. 





Fractional part 
20090401 

Galina pose la question : What fractional part of eight is eight hundredths Stephen La Rocque lui répond. 





Partial derivatives 
20090117 

Meghan pose la question : I have a question I've been working at for a while with maxima/minima of partial derivatives.
"Postal rules require that the length + girth of a package (dimensions x, y, l) cannot exceed 84 inches in order to be mailed.
Find the dimensions of the rectangular package of greatest volume that can be mailed.
(84 = length + girth = l + 2x + 2y)" Harley Weston lui répond. 





Partial variation 
20081103 

Diamond pose la question : what are the 2 parts of partial variation? Penny Nom lui répond. 





Integration 
20081017 

hazela pose la question : integration of
x sinx cosnx Harley Weston lui répond. 





Integration by parts 
20080130 

seth pose la question : hi i really dont understand integr
ation by parts. for example, the integral(t^2sintdt. i have u=t^2 and v'=sint also u'=t^/3 v=cost
for the formula i have uvintegralvu' dx this is all well and good but i cant get it right. Harley Weston lui répond. 





A large concrete shape 
20080116 

Keith pose la question : what is the cubic yards of an area that is not a perfect 1/4 circle?
The dimensions are 100ft. x 60ft. x 125ft. curcumferal arch x 3ft. depth? Stephen La Rocque lui répond. 





Partial fractions 
20080106 

taiwo pose la question : i copied the question below from john bird's higher engineering mathematics
fourth edition (pg 19) after solving all the partial fraction questions from the book
except this:
x^3 + 4^2 + 20x  7 over (x1)^2 (x^+8). i will appreciate it if you help me out so i can
know whether their answer is correct. thanks alot Harley Weston lui répond. 





Partitioning a clock face 
20071219 

Kim pose la question : Using a clock with a regular circular faced dial, draw two straight lines such that the sum
of the numbers in each of the three areas is equal. The team at Math Central lui répond. 





Dividing a circle 
20071123 

matt pose la question : hi. can you please send me a diagram of how to draw 3 lines in a circle to get 8 sections. Stephen La Rocque lui répond. 





Motion along a line 
20071002 

Claudette pose la question : If the position function of a particle is x(t) = sin^2(2t), find the distance that the particle travels from t = 0 to t = 2 Harley Weston lui répond. 





Integration 
20070202 

Jenna pose la question : How do I integrate ( ln(x) ) / ( x^2 ) ? Penny Nom and Claude Tardif lui répond. 





Can one divide a circle into 4.5 parts 
20060330 

Chris pose la question : If it is possible, can one divide a circle into say, 4.5 parts (with 4 equal parts and a half part)?
Or for that matter, for any integer, n, into n/2 parts as above?] Walter Whiteley lui répond. 





A partial derivative 
20040319 

Penny Nom pose la question : Is it possible to differentiate the following equation, if so could
you please explain.
S=SQRT(T(5/X^2))
I would like the derivative of S with respect to X. Harley Weston lui répond. 





Integrating e^x sin(x) 
20030503 

Lech pose la question : I am having trouble integrating the following expression by parts: ex sin(x) I used the integrator at http://www.integrals.com/ to find the solution, ? 1/2 ex cos(x) + 1/2 ex sin(x). This is easy to confirm by differentiation, however I am confounded as how to arrive at the answer. Penny Nom and Claude Tardif lui répond. 





Two problems 
20021014 

Eva pose la question :
a) How many different equivalence relations can be defined on the set X={a,b,c,d}? b)Show that 6 divides the product of any 3 consecutive integers. I know it is true that 6 divides the product of any 3 consecutive integers. However, i have problem showing the proof. Leeanne Boehm and Penny Nom lui répond. 





Dividing a circle 
20011017 

Ahmeen pose la question : I am having a hard time figuring out how a circle can be divided into 11 equal parts with only 4 cut allowed? My teacher gave this to us and I still can't cut my pie into eleven equal parts with only four cuts. Walter Whiteley lui répond. 





Integration by parts 
20010409 

A student pose la question : how do you integrate x tan^{1}x dx, i know it can be done by integration by parts maybe, but i'm not sure.... Claude Tardif and Harley Weston lui répond. 





Two integrals 
20010403 

Jim pose la question : I'm having trouble with these integrals. Can you help me out? 1)the integral of:
x^{5} arctan x dx 2)the integral of:
2x^{5} + 9x^{4} + 19x^{3} + 13x^{2}  5x  25  dx x^{4} + 4x^{3} + 5x^{2} Claude Tardif lui répond. 





Part of a part 
20010211 

Katie pose la question : Hello! I was looking at your Fraction questions and since i am pursuing to be an elementry school teacher i feel i don't understand one of your responses. How would you explain this to an elem, midd, and high school student. Even me myselfin college really does not understand. The question was: When you multiply two positive fractions less than 1, how does the answer compare to the size of the fraction? Why? Penny Nom lui répond. 





Congruent parts of congruent figures 
20000310 

Erica pose la question : Yesterday, I recieved a test problem asking to prove two line segments equal. Here is the problem as I was given it: Given: paralleogram ABCD AE is perpendicular to DB CF is perpendicular to DB Prove: AE is equal to CF I answered the problem as follows: . . . Walter Whiteley lui répond. 





Party favors 
20000222 

Krystina Fernandez pose la question : Luanne was making party favors for her little sister's birthday party. Each party favor was in the shape of a cube. Luanne had pink and purple paint to paint the cubes and she could paint each face only solid pink or solid purple (no dots,stripes,ect.).For example, one cube may be all purple, another may have two purple faces and four pink faces. Her little sister wanted to have a different cube for each guest.(A cube is not considered different if it can be turned so that all it's sides match the corresponding sides of another cube.)How many different cubes was it possible for Luanne to make? Claude Tardif lui répond. 





Calculus problems 
19980713 

Lorraine pose la question : I'm stuck again. Can you help? This involves integration using the method of partial fractions the integral of: 7x(to the 5th)  2x(cubed) + 3 dx  x(to the fourth)  81 Do I have to do long division to reduce the numerator to the fourth power? the integral of: 4 16x +21x(squared) + 6x(cubed)  3x(fourth) dx  x(cubed)(x  2)(squared) Lorraine Harley Weston lui répond. 

