







Grade 9 Algebra 
19980607 

From Tarah Kostenko: I am a grade 9 student and I cannot figure out how to solve these two similar problems. can you please help? 3(y1/2)=1/2 also 2/3(x + 1)=6 I don't come up with the same answers as the book and I can't figure out what I'm doing wrong. Thank you,
Answered by Harley Weston. 





A Logic Problem 
19980607 

From Anthony Bacigalupo: My name is Anthony Bacigalupo and I take Sequential ][ Math and am taking a practice regents. When doing a logic problem, I encountered the following statements, where I am trying to prove P ( I left out steps unrelated to the question).... Answered by Chris Fisher. 





A trig limit 
19980528 

From Ann: This problem is a calculus 1 limit problemhigh school level. I'm teaching myself calc over the summer and I'm already stumped. find the limit lim sec^(2)[(sqrt2)(p)]1 p>0  1sec^(2)[(sqrt3)(p)] I'm Ann. Answered by Harley Weston. 





Sequences and series 
19980527 

From Michael Le Francois: The sum of the first ten terms of an arithmetic series is 100 and the first term is 1. Find the 10th term. The common ratio in a certain geometric sequence is r=0.2 and the sum of the first four terms is 1248 find the first term. Answered by Penny Nom. 





Trigonometry history 
19980526 

From Joeseph Huckler: Can you please tell me some history of the trigonometric ratio Tangent? who discovered it? when was it discovered and some other useful info... Answered by Penny Nom. 





A Place Value Curiosity 
19980525 

From Ed: I was visiting with an elderly gentleman this afternoon. He showed me this curiosity and then asked if I could explain it to him. Can you provide an explanation of why the 9 or multiple of 9 keeps occurring in this procedure? Choose any number, say 125 and add the digits to get 8. subtract the 8 from the 125 and the result is 117. Add the digits in 117 to get 9. Subtract the 9 from the 117 to get 108. Add the digits in 108 to get 9. If this procedure continues a 9 or a multiple of 9 reoccurs. What is the mathematical explanation behind this happening? Answered by Denis Hanson. 





The Fourth Dimension 
19980524 

From Whitney Page: Okay, here goes all my effort to try to explain shat I'm trying to ask of you. It's about something I read in a book called A WRINKLE IN TIME, by Madeline L'Engle. It's called tesser, or tesseract. It talks about first diminsion, a straight line, second diminsion, a flat square, and third diminsion, a square with sides, front and back, top and bottom. I can picture all of that. Then it says that fourth diminsion is when you square the three diminsional square. It also described the fourth diminsion as time. I can't figure out how that can be. Then it says... Answered by Chris Fisher. 





Percentage Question 
19980518 

From Eddie Knox: Example: If I have a recipe calling for 16 ounces of 4% vinegar (vinegar which has been diluted with water to a strength of 4%), and all I have on hand is 16 ounces of 5% vinegar, how much water should I add to decrease the strength to 4%, before measuring the 16 ounces to be used. I'll appreciate any insight and help. Thank you so much! Answered by Harley Weston. 





Graph question 
19980512 

From Rose Seminary: Why is the point of intersection of two lines the solution to the corresponding system of equations? Answered by Penny Nom. 





Isosceles trapezoid formula 
19980512 

From Donna McMullin: The teacher of Gifted and Talented Math has been trying to locate the formula for anisosceles trapezoid and we can't find it anywhere. Could it be the same formula for that of a parallelogram ? Please advise. Answered by Walter Whiteley. 





Un angle solide 
19980506 

From Giol: Qu'est ce qu'un angle solide ?? J'ai beau chercher dans mes documents, je ne trouve rien de bien convaincant sur le sujet si ce n'est une définition qui me semble bien vague et creuse ... En vous remerciant de votre attention ( puissiez vous illustrer votre réponse par un exemple, s.v.p...) Bonjour,
Answered by Chris Fisher. 





Area Calculation 
19980505 

From Jessica: There's a question I have that I hope you can answer about calculating area. It seems to me that common sense says that if you have say 100 meters of fence, the area you can enclose should be a constant. Yet the math says it is not so. For example if you build a rectangle 10x40 the enclosed area is 400 square meters. But if you build a rectangle 5x45 then the area is 225 square meters, even though you've started with the same amount of fencing. I know this is true, but can anyone explain IN ENGLISH why this is so? Answered by Harley Weston. 





Pyramid 
19980504 

From Lisa Nathan: How do you find the area of a pyramid? Answered by Harley Weston. 





Mathematical Arrays 
19980501 

From Gene Lanctot: Could someone please explain what a mathematical or arithmetical array is? The array in question is used in grade three math in Ontario. I would also like to know what its purpose is. Answered by Harley Weston. 





Multiplying by Nine  Chismbop Style 
19980427 

From Noria Jones: About a year ago a grade 5 teacher at my son's school taught the children how to multiply the 9 times table on their fingers quickly. It was part of a kind of finger math kind of thing... Answered by Patrick Maidorn. 

