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1-tan^3t/1-tant=sec^2t+tant |
2007-10-23 |
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From Brian:
I need help proving:
1-tan^3t/1-tant=sec^2t+tant
Answered by Harley Weston. |
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Arc length and height in a circle |
2007-10-23 |
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From Bruce:
I have been trying to find a formula that relates height of a segment
from the bottommost point of a circle toward the center of the circle to
the corresponding distance along the circumference of the circle
(i.e. at the point on the circumference intersected by a line perpendicular
to that segment). The unknown variable is the height of the segment;
the known variables are the radius of the circle and the distance
along the circumference.
Answered by Stephen La Rocque. |
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An equilateral triangle with height 2 inches |
2007-10-23 |
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From Christine:
I'm doing an project in school about tessellations.
But first, I have to construct an equilateral triangle with an altitude of exactly 2 inches.
I know how to draw an equilateral triangle...but I don't know what I have to do in order for the triangle to have an altitude of 2 inches.
Answered by Penny Nom. |
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Choosing 3 crayons from 6 crayons |
2007-10-23 |
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From Greg:
I have six crayons: red, orange, yellow, green, blue, and purple. I need to know how many combinations of three crayons can I have.
Answered by Penny Nom and Melanie Tyrer. |
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BEDMAS |
2007-10-23 |
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From brit:
(5+4)-7*4/28+8
Answered by Melanie Tyrer. |
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Turn 81 into the power of three |
2007-10-22 |
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From Victoria:
I do not understand how to turn 81 into the power of three.
Answered by Penny Nom. |
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Mixing planting soil |
2007-10-22 |
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From Ken:
Stephen owns a gardening supply store that sells two brands of planting soil, each of
which contains plan food. Brand A contains 10% plant food, while brand B contains
7% plant food. To accommodate a customer, the store will combine the two brands to
make 3 lbs of an 8% plant food mixture. How much of brand A and brand B should
be used?
Answered by Stephen La Rocque. |
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The distance of the Andromeda Galaxy |
2007-10-22 |
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From ROLY:
What is 2.5 million miles x 6 trillion miles (light year)
This is the distance of the ANDROMEDA Galaxy.
Answered by Stephen La Rocque. |
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Maximize profit |
2007-10-22 |
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From Dina:
A meat market purchases steak from a local meat packinghouse. The meat is purchased on Monday at a price of $2 per pound, and the meat market sells the steak for $3 per pound. Any steak left over at the end of the week is sold to a local Zoo for $0.50 per pound. The demand for steak and the probabilities of occurrence are as follows:
Demand Probability
20 10%
21 10%
22 15%
23 20%
24 20%
25 15%
26 10%
Determine the amount of stock to maximize the profit. Draw the graph and explain.
Answered by Penny Nom. |
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An algebra exercise |
2007-10-22 |
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From Math:
The number of moles of an ideal gas can be found from the formula:
PV/RT=N
solve the formula for "R", the ideal gas constant.
Answered by Penny Nom. |
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The rate of change of the area of a triangle |
2007-10-22 |
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From Ahlee:
So my question is:
The included angle of the two sides of a constant equal length s of an isosceles triangle is ϑ.
(a) Show that the area of the triangle is given by A=1/2s^2 sinϑ
(b) If ϑ is increasing at the rate of 1/2 radian per minute, find the rate of change of the area when ϑ=pi/6 and ϑ=pi/3.
(c) Explain why the rate of change of the area of a triangle is not constant even though dϑ/dt is constant
Answered by Penny Nom. |
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The perimeter of an acre |
2007-10-22 |
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From juliana:
how many times can i walk around 2 acres of land to equal 1 mile?
Answered by Penny Nom. |
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sin 43= y/20 |
2007-10-21 |
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From stefany:
if sin 43= y/20, what is the value of y to the nearest tenth?
Answered by Penny Nom. |
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Two probability density functions |
2007-10-21 |
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From ravinder:
A program consists of two modules executed sequentially.
Let f1(t) and f2(t) respectively denote the probability density functions
of time taken to execute the two modules. The probability
density function of the overall time taken to execute the program is
given by
(1) f1(t) + f2(t)
(2) INTEGRAL OF(f1(x)f2(x)dx) from 0 to t
(3) INTEGRAL OF(f1(x) f2(t-x) dx) from 0 to t
(4) max{f1(t), f2(t)}
Answered by Andrei Volodin. |
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A multiple choice exam |
2007-10-21 |
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From jon:
a student is taking a multiple choice exam in which each question has four choices.
assuming that she has no knowledge of the correct answers to any of the questions, she
has decided on a strategy in which she will place four balls (marked A, B, C, D) into a box. she randomly
selects one ball for each question and replaced the ball in the box. the marking will determine her answer to the question.
there are five multiple choice questions on the exam. what's the probability that she will ...
Answered by Stephen La Rocque and Harley Weston. |
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