 |
|
|
|
|
|
|
|
|
Percentage markup |
2004-06-04 |
|
From A parent:
if our cost is 54.00 and their cost is 117.00 what is the percentage of mark up?
Answered by Penny Nom. |
|
|
|
|
|
|
A tangent to a quadratic |
2004-06-04 |
|
From Jem:
I have a question on the tangent to a quadratic curve.
Say I have a curve y = ax2 + bx + c. The gradient, using the derivative of y, at any point x on the curve is: 2ax + b right? Then, for the tangent that cuts the curve at a point x, the equation of the tangent can be: y1 = (2ax + b)x1 + d.
My question is, how is the point d of this tangent determined? It is the point on the y-axis where the tangent cuts isn't it? Is there a formula for it?
Answered by Penny Nom. |
|
|
|
|
|
|
The game of 24 |
2004-06-04 |
|
From Samantha:
i have the game 24 (the one where you have to use multiplication, division, addition, and subtraction to get to the answer 24) I was playing when i came across the 4 numbers 20, 17, 7, 11 and i cant seem to get 24.
Answered by Claude Tardif. |
|
|
|
|
|
|
Divisors of 2n+1 and 3n+9 |
2004-06-02 |
|
From Chris:
Amy selected a positive integer N and wrote numbers 2xN+1 and 3xN+9 on a whiteboard. Boris looked at the two numbers on the whiteboard and wrote in his notebook a positive integer that divides each of them. Find all possible numbers that Boris could have written in his notebook.
Answered by Chris Fisher and Penny Nom. |
|
|
|
|
|
|
Cubic yards in a pool |
2004-05-30 |
|
From Jerry:
HAVE A AREA WHERE I HAD A 18 FOOT ROUND POOL.
THE DEEPEST PART IT WAS IN THE GROUND WAS AROUND 7 INCHES TAPERING DOWN TO AROUND 4 TO FIVE INCHES AND A LITTLE OF THE ONE SIDE ALMOST AT GROUND LEVEL...HOW MANY YARDS OF DIRT WOULD I NEED TO FILL IT IN???? IS THERE A FORMULA FOR THAT.......COULD YOU FIGURE THAT FOR ME?
Answered by Penny Mon. |
|
|
|
|
|
|
The Parliament of the land of Achronia |
2004-05-29 |
|
From Christine:
The Parliament of the land of Achronia consists of two houses. The parliament was elected in 2003 for a period of six years beginning on Thursday, the 1st of January 2004, when the two houses had their first sessions. According to the rules, the meetings of the first house must occur every twelve days for the duration of the term, and the meetings of the second house must occur every eighteen days. For example, the second meetings of the first and the second houses were held on the 13th and 19th of January respectively. A new law can be passed on any day when both houses meet, except on a Thursday. On how many days can the parliament members pass new laws during this six year term?
Answered by Penny Nom. |
|
|
|
|
|
|
112! |
2004-05-28 |
|
From Beatriz:
1) A bus driver collects identical sets of 5 coins from each passenger. If the totoal colledted was $21.83, how many pennies did the driver get??
2) How many terminal zero in the base 10 expression of 112! (factional) N! means N(N-1)(N-2) .....(2) (1).
Answered by Penny Nom. |
|
|
|
|
|
|
Different infinities |
2004-05-27 |
|
From Plober:
How can I explain to a friend (in a bar, using as a pen and a paper napkin) that the integer's infinity is 'smaller' than the irrationals's one? The demo I tried was that you couldn't match the integers with the real numbers between 0 and 1 (that 0.xxxxx replacing the Nth number from a different one... that demo), but she used my argument >:| saying that you can add one to the integer's infinite, and the number I was creating was only one more...
I can't think of any other way, and I KNOW the real's cardinality is greater than the integer's one
Answered by Claude Tardif and Penny Nom. |
|
|
|
|
|
|
English |
2004-05-27 |
|
From Chang:
well my question is i was told by most of the teachers that ''think in english'' is the best way to learn english but how can i do like that do i need to know about the stucture first or do i need to learn the western culture ?
here is a sentence i have translate directly from my mother language.'' i was given an admiration of sincerity from this client on the follow up action i have done in the complaint.
Answered by Claude Tardif. |
|
|
|
|
|
|
The horizontal fraction bar |
2004-05-27 |
|
From Kashia:
What is the name of the bar that separates a numerator and that denominator?
Answered by Penny Nom. |
|
|
|
|
|
|
The center of a circle |
2004-05-26 |
|
From Wan:
I am trying to find the radius of an arc. The only things i know about the arc is all referenced from the line of tangency to the arc. on both sides i have a differnt horizontal perpendicular distance to the point of tangency.
left side |-------*---------------| right side (*=point of tangency). Then i have 2 difference vertical perpendicular distance of the end points to the line of tangency. I know it sounds very bad in text but this is all i know about the arc. Can you help me find the radius?
Answered by Penny Nom. |
|
|
|
|
|
|
The base of a triangle |
2004-05-25 |
|
From Ralph:
With a 30 degree angle at the top of a triangle and a height of 15 what is the base?
Answered by Penny Nom. |
|
|
|
|
|
|
Programming without trig functions |
2004-05-25 |
|
From Derek:
I am a programmer trying to calculate the following.
What is the formula to find the cross-sectional area of a cylinder with out using any trig functions? or better yet, how can you calculate any given volume in a cylindrical tank with spherical heads with out trig functions?
I am using a PLC (programmable logic controller) to do this and trig functions are not available.
Answered by Harley Weston. |
|
|
|
|
|
|
Finding bearings |
2004-05-24 |
|
From James:
This question is about finding bearings. A boat race starts from point A, goes North to Point B, a distance of 1000 meters. The course is triangular. The bearing from point B to point C is South 70degrees West. The distance from Point B to point C is 1500 meters. Find the course bearing from C to A.
Answered by Penny Nom. |
|
|
|
|
|
|
Some trig expressions |
2004-05-23 |
|
From A student:
Prove:
sin A + sin B = 2sin(A+B/2)cos(A-B/2)
cos A - cos B = -2sin(A+B/2)sin(A-B/2)
cos A + cos B = 2cos(A+B/2)cos(A-B/2)
sin A - sin B = 2cos(A+B/2)sin(A+B/2)
Answered by Penny Nom. |
|
|
