 |
|
|
|
|
|
|
|
|
The rate of change of y with respect to x |
2010-04-29 |
|
From Tom:
I just had a quick calc question about wording that wasn't ever
addressed in class. When the book says "the rate of change of y with
respect to x", should it be considered how fast y is changing in
comparison to x?
I ask because the textbook says that "y is changing 3 times faster than x,
so the rate of change of y with respect to x is 3." I'm use to rate being
like velocity, as in units of distance per units of time. All we're told
in class is that it's the slope of the tangent line, I was hoping you
could clarify for me what exactly is meant by the wording of a "rate of
change of something with respect to something else". More specifically, what
"rate" and "with respect to" mean within this context?
Thanks for your time
Answered by Harley Weston. |
|
|
|
|
|
|
A trig equation |
2010-04-28 |
|
From Steve:
2cos^2(X)-2sin^2(x)+1=0
Answered by Harley Weston. |
|
|
|
|
|
|
The width of a picture frame |
2010-04-28 |
|
From Daniel:
The frame of a picture is 28 cm by 32 cm outside and is of uniform
width. What is the width of the frame if 200 cm ^2 shows?
Answered by Penny Nom. |
|
|
|
|
|
|
A circle inscribed in a square inscribed in a circle |
2010-04-28 |
|
From jouniella:
A square is inscribe to the first circle, then another circle is inscribe to the square. Find the ratio of the 2 circles.
Answered by Penny Nom. |
|
|
|
|
|
|
A rectangular laundry room |
2010-04-28 |
|
From Cynthia:
a laundry room is shaped like a rectangle. the area of the room is 6 square yards. the perimeter is 10 yards. The room is longer than it is wide. How wide is the room? How long it the room?
Answered by Penny Nom. |
|
|
|
|
|
|
cos(x) = sin(x - 1) |
2010-04-28 |
|
From alex:
In the equation cos x = sin x-1 for -pi/2
A: solve for x graphically
B: solve algebraically and prove the solution is correct.
Alex
Answered by Penny Nom. |
|
|
|
|
|
|
y = - log(x) |
2010-04-28 |
|
From Alex:
y= - log(x), where y = 4.3
solve for x.
Answered by Harley Weston. |
|
|
|
|
|
|
Sales taxes in Quebec |
2010-04-28 |
|
From carole:
I work at a company where we use transport companies and we often get credits
on their invoices. I need to know how to subtract the sales taxes from these credit amounts.
(5% TPS and 7.5% TVQ).
Is the equation: Amount / 1.05 = then this amount / by 1.075=?
Answered by Penny Nom. |
|
|
|
|
|
|
Adding five positive integers that have a product of 48 |
2010-04-27 |
|
From Lorraine:
What is the smallest possible sum that can be obtained by adding five positive integers that have a product of 48.
Answered by Chris Fisher. |
|
|
|
|
|
|
The "vertex" of a cone |
2010-04-27 |
|
From Tom:
By definition a vertex is a point where three edges meet in a 3 dimensional object.
My ten year old son argues that the point at the top of a cone is not a vertex since it does not fit the definition. He got the answer wrong on a test recently but insists that he is right. I need a mathematician to answer this for him.
Answered by Robert Dawson and Chris Fisher. |
|
|
|
|
|
|
One in twenty as a percentage |
2010-04-27 |
|
From jim:
Please advise how I work out a gradient of say 1-20 one in twenty as a percentage %
Answered by Penny Nom. |
|
|
|
|
|
|
A rectangular prism |
2010-04-27 |
|
From Savannah:
A rectangular prism is made of exactly 8 cubes. Find
the length, width, and height.
Answered by Penny Nom. |
|
|
|
|
|
|
Rolls of sod |
2010-04-27 |
|
From judy:
My yard is 35 feet by 29 feet. I want to put sod on the entire yard.
The rolls of sod are 9 square feet. How many rolls of sod will I
to complete the job?
Answered by Penny Nom. |
|
|
|
|
|
|
Polyhedra and polygons |
2010-04-26 |
|
From Brandon:
What is the difference between a polyhedra and a polygon?
Answered by Penny Nom. |
|
|
|
|
|
|
Tiles |
2010-04-25 |
|
From Pat:
how many 6 inch tiles will I need to purchase for an area that is currently covered with 351 4 inch by 4 inch tiles.
Each box of 6 inch tiles states it contains 16 pieces and covers 4 square feet.
Answered by Penny Nom. |
|
|
