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Computing confidence intervals |
2004-11-26 |
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From Christie:
I was given a question with N=100, sample proportion is 0.1- compute the 95% confidence interval for P? I have tried this several ways but do not know how to do without means, standard deviations, standard error of the mean? I asked my teacher and she said I have all the info I need. Can you help????
Answered by Penny Nom. |
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A right triangle |
2004-11-24 |
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From Bruce:
In triangle ABC.
Angle ABC is 90 degrees.
Side AB measures 34.
Side BC measures 31.
What does side AC measure?
Answered by Penny Nom. |
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Slicing cubes |
2004-11-23 |
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From Anthony:
You are working with a power saw and wish to cut a wooden cube 3-inches on aside into 27 1-inch cubes. You can do this by making six cuts through the cube keeping the pieces together in the cube shape. Can you reduce the number of necessary cuts by rearranging the pieces after each cut?
Answered by Chris Fisher. |
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Cost before the markup |
2004-11-23 |
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From Norman:
the sum of eg $130 includes the markup of 30%.
However I need to calculate the percentage to apply to the $130 to assess the cost ie $100.
Answered by Penny Nom. |
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A graph with certain properties |
2004-11-22 |
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From A student:
i was asked as a question in coursework to sketch the graph with the following characteristics:
a double root at -3
a pair of imaginary roots
an x-intercept at 6
a root at 4 which is not a double root
Answered by Penny Nom. |
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Combinations |
2004-11-22 |
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From Vivek:
Show that
10C0 + 10C1 + 10C2 + 10C3+.....10C10 =1024
Answered by Penny Nom. |
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The length of an arc |
2004-11-21 |
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From Daryl:
I am tying to find the arc length of a line 6' and the vertex of the arc 1' off of the line. that is all that is known
Answered by Penny Nom. |
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Is a square a rectangle? |
2004-11-21 |
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From Carol:
I am a teacher. In an FCAT sixth grade review test, there was a question to the students to draw a square and then they referred to it as a rectangle.
What is the definition that makes a rectangle a square that can be taught to the students without confusing them.
Answered by Walter Whiteley. |
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Proof by induction |
2004-11-20 |
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From Vic:
Problem: Find the first 4 terms and the nth term of the infinite sequence defined recursively as follows:
a(1) = 3 and a(k+1) = 2a(k) for k -> 1.
Note: Quantities in brackets are subscripts
-> means 'equal to or greater than'.
Using the recursive formula, the first 4 terms are;
a(1) = 3, a(2) = 6, a(3) = 12, a(4) = 24
The nth term a(n) = 2n-1 x 3 (equation 1)
Equation 1 must be proven using mathematical induction. This is where I am having a problem.
Answered by Penny Nom. |
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Solving quadratics |
2004-11-20 |
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From Aaron:
Can you solve the following equation (quote the value of x,y and t to 3 sig figs)
((i have changed figures so that i can work through my own example))
x2 + x - 6 = 0
5y2 +19y = 3
10cos2 t + 3cos t = 4
Answered by Penny Nom. |
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Construction of a cone |
2004-11-20 |
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From John:
I am a builder working on a project where I need to make a cone. It's a right circular cone with 15" base radius and slant angle of 30 degrees. I want to cut it out of flat sheet metal then bring the edges together to form the cone. Is this enough information?
Answered by Penny Nom. |
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A sequence |
2004-11-19 |
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From Liucy:
Find the Nth term:
10 40 90 160 250
Answered by Penny Nom. |
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Volume of a box |
2004-11-18 |
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From Catherine:
I need to find a formula to calculate the amount of liquid would hold. maybe the volume or something. its a square box used to hold liquid on a farm . we want to measure how much liquid it can hold.
Answered by Penny Nom. |
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1/4 tsp salt = ??? grams |
2004-11-16 |
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From Julie:
if i have 1/4 teaspoon of salt how many grams does that equal
Answered by Penny Nom. |
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Equations involving radicals |
2004-11-16 |
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From Merin:
I am quite confused about solving radical equations. This is what I understand:
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V x-3 = 3
Then you would square each side to get ride of the radical sign and then you solve the problem from there. (x=12 right?)
However, what about a problem with two radicals? For example:
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V x-2 + V 3x-3 = 3
No matter what I try I cant get the right answer!! Please help!!!
Answered by Penny Nom. |
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