







Deriving the Quadratic Formula 
19970204 

James pose la question : How do you derive the quadratic formula? I know what it is, but the textbook doesn't say how to derive it. Penny Nom lui répond. 





Parabolic Mirrors 
19970128 

Megan Wennberg pose la question : Consider a ray of light that passes through a chord of a parabola (the chord is above the focus and parallel to the directrix), hits the parabola at a point (x,y) and is reflected through the focus. If d1 is the distance from the chord to the point of incidence (x,y) and d2 is the distance from (x,y) to the focus, can you prove that the sum of the distances d1+d2 is constant, independent of the particular point of incidence. Penny Nom lui répond. 





A donkey and his carrots 
19970128 

Emily Lind pose la question : There is a donkey who carries carrots. A farmer has 3,000 carrots to carry to the market. The market is 1,000 miles away. The donkey can only carry 1,000 carrots at a time and he eats 1 carrot every mile that he walks but this is only when he is carrying carrots. How many carrots can the farmer get to market by having the donkey carrying them? Penny Nom lui répond. 





Repeating Decimals 
19970124 

Grant Reed pose la question : Is there a way to tell that the repeating decimal for 1/17 has no more than 16 repeating digits? Penny Nom lui répond. 





Foci of an Ellipse 
19970122 

David Gilliam pose la question : How do I find the focii of the following equation? 4x^2 + 9y^2 = 36 Harley Weston lui répond. 





Mathematics of Schedules 
19970116 

Byron Krull pose la question : I was asked if there was a mathematical method to work with schedules. The problem is this. There are 24 teams playing weekly on 4 sheets at 3 different times of the day as follows... Denis Hanson lui répond. 





Three Spheres 
19970114 

Alan Schnerch pose la question : Three spheres of diameter 2 are placed on a level surface so that each sphere touches the other two. A fourth sphere, also of diameter 2, is placed on top of the other three so that it touches all of the other spheres. The distance from the level surface to the highest point of the top sphere is . . .. Chris Fisher and Harley Weston lui répond. 





A triangle problem 
19961219 

S. Johnson pose la question : Given that Triangle ABC is a right triangle and Circle O is inscribed in it find the radius of Circle O, totally in terms of a, b, and c. Penny Nom lui répond. 





A trig problem 
19961213 

S. Johnson pose la question : sin t + cos t = 1/5. Find ALL exact values of cot t, given the original equation. Harley Weston lui répond. 





Roots of a Polynomial 
19961206 

Paula Miller pose la question : Why is the solution called a "root"? Why not just the "xintercepts"? Chris Fisher and Harley Weston lui répond. 





Sides in a Regular Polygon 
19961206 

Rick Moss pose la question : If you are given the measure of each interior angle (162 degrees) of a regular polygon. How many sides does the polygon have? Penny Nom lui répond. 





A balance problem 
19961118 

Jack N. Bussell pose la question : There are 12 coins which look exactly the same, however one of them is heavier or lighter than the rest. Using a pointer balance scale, can you identify the odd coin and whether it is heavy or light in 3 weighings? Harley Weston lui répond. 





Pentominoes 
19961114 

Sam Maraldo pose la question : What is a pentominoe? I need to understand the concept and how/why it is used? Penny Nom lui répond. 





Trigonometry 
19961112 

Evans pose la question : Any idea who came up with some or most of the ideas involved in trigonometry? Chris Fisher lui répond. 





Smith, Rodriguez and Jones 
19961107 

Rafayel Ambartsumyan pose la question : On a train, Smith, Rodriguez, Jones are the fireman, brakeman, and engineer, but not in that order. Also aboard the train are three businessman who have the same names, a Mr. Smith, a Mr. Rodriguez, and a Mr. Jones. ..... Who is the engineer? Penny Nom lui répond. 

