







Shooting a ball at a target 
20160216 

Thys pose la question : Hi
I have a problem with the formula that i use .(for programming)
I have looked all over the web to find a solution but no luck.
I have a cannon that shoots a ball at a target
I use this formula to calculate what my initial velocity must be to hit the target
at a angle of 30 degrees and a distance of 15m (the cannon and target position is known)
It works perfectly if both is at same height but if one is higher or lower it miss.
In an example I am working with the range is 30m, the angle is 45 degrees and the target is 10m higher than my position.
Please help
Formula = V0 = √RG / Sin(2α) Harley Weston lui répond. 





a^(2^n) 
20101022 

Tim pose la question : I am trying to understand a^(2^n).
The hint they give is a^(2^(n+1)) = (a^(2^n))^2
I am writing a program that will solve a^(2^n) recursively but need to
understand the power before I begin.
I am currently pursuing writing (a) x (a^(2^(n1))) where the
(a^(2^(n1))) would be the recursive function call a n approaches 0.
Once n is 0, the result would be multiplied by a two more times.
Anyway, explaining these powers would be appreciated. I will most likely
complete the program before the answer but I want to understand the
logic of these powers. Thank you, Tim Stephen La Rocque lui répond. 





Papy's Computer 
20020111 

MaryAnne pose la question : My secondgrade son brought home a fun math worksheet which involved calculating sums using "Papy's Computer." I had never heard of this before and found it to be quite interesting. Each digit in a decimal number is represented by a 2x2 grid. Each grid square corresponds to one of the numbers 1,2,4, or 8. Harley Weston lui répond. 





Calculator and telephones keypads phones 
20000627 

Thomas Smith and Veronica YatesRiley pose la question : On a keyboard, why is the number "7" on the top of the keypad as opposed to the number "1" at the top a telephone keypad? Penny Nom lui répond. 





Computer use in mathematics classrooms. 
19990623 

Rosemary Greer pose la question : Can you give me any information, either articles or the names of books, concerning the use of computers in the math classroom? Lillian Perivolaris lui répond. 





Intersection of planes 
19981122 

Dave Rasmussen pose la question : I am a teacher of secondary mathematics with a question about the uses of Three Dimensional Coordinate Geometry. I have been teaching my students to write equations of planes and lines,  to find the intersection of these and the distance between them. What I am having difficulty finding are good applications of these techniques to "real world" situations. Can anybody help me? Walter Whiteley and Harley Weston lui répond. 

