Mathematics - 5 December 2007

Normally, set x is considered equal to set y if x={A,B} and y={B,A}. However, for my question let's assume {A,B} = {B,A} is NOT true because of the sequence of their members. We have a set c with n number of unique elements. How many subsets can there be for the set c if:
*{A,B} and {B,A} are not considered equal or same
*Each subset has maximum two elements
*An element is not repeated in the subset

Is there any specific term for above mentioned phenomenon?

2007-12-05 17:53:54 · 3 answers · asked by szhob 3

A guy welding together a large cube using angle iron for the edges notices that the cube is not very rigid. So he decides to weld on some diagonal braces, going from any one corner to another. How many braces does he need to make the cube rigid? Assume that each member is rigid, but that all joints are flexible. Crossing diagonals may be welded together.

The reason for this 2nd repost is because some may have more to say on this problem. Can it be done with fewer than 6 diagonals?

See original question and answers:

http://answers.yahoo.com/question/index;_ylt=AlYz35VsYz6Wtfwv0bdO3.7sy6IX;_ylv=3?qid=20071205004208AARoBvf

2007-12-05 17:53:04 · 4 answers · asked by Scythian1950 7

An after shave lotion contains 50% ethyl alcohol. How much water must be added to 6 fluid ounces of this lotion to reduce it to one which is 75% nonalcoholic?

2007-12-05 17:49:23 · 5 answers · asked by precious 3

Its for a test tommorow. (studying)

STEP BY STEP

EXPLAIN

2007-12-05 17:44:13 · 3 answers · asked by Anonymous

k so im terrible at math and cannot figure this out...if I take a multiple choice test thats out of 45 and I need a 67% to pass the test how many can I afford to get wrong?

2007-12-05 17:43:12 · 7 answers · asked by Anonymous

ok help me out plz ...
1.P and Q working together an do a job 4 days, Q and R can do the same job in 3 days, P and R in 2.4 days. How long will they take to finish job independently.

2. 5 tables and 8 chairs costRs.11500, 3 tables and 5 chairs cost Rs.7000. What is the cost of chair and table.

3.If 1 pump an fill a pool in 16 hrs and if 2 pumps can fill the pool in 6 hrs, how fast can 2 pump fill the pool

4. If 8 men take 12 days to assemble 16 machines how many days will it take 15 men to assemble 50 machines

2007-12-05 17:42:42 · 1 answers · asked by Chainz chIzzEl 1

Sumnation of (1+1/n)^2*e^-n where n=1 to infinite

2007-12-05 17:41:19 · 3 answers · asked by Anonymous

how do you dind the equation of the tangent line f(x)=x√(1+x^2) at (1,√2).

2007-12-05 17:38:03 · 3 answers · asked by elva1989 1

Give the formula for its nth term also and show the addition of those two terms.

2007-12-05 17:35:12 · 2 answers · asked by sv 7

Suppose that we were going to conduct a study to determine if there is an increased risk of getting lung cancer based on whether the person excerises regularly or not. In our excerising regularly group(1), we find than 2 out of 100 get lung cancer. In our non excersing group(2), we find that 5 out of 100 get lung cancer. What is the sample relative risk? (Give to one decimal place.)


And best answer will not go to anyone who tells me "do your own homework" (surprise surprise) If I knew how to do this, or how to find out, I wouldn't be wasting the time or the points.

2007-12-05 17:32:13 · 7 answers · asked by Mrs. Eric Cartman 6

9. A new test is developed to test for a certain disease, giving "positive" or "negative" results to indicate that the person does or does not have the disease. For a person who actually has the disease, the test will give a positive result with probability 0.95. For a person who does not have the disease, the test will give a positive result with probability 0.05. Furthermore, only one person in 1000 actually has the disease. If a randomly selected person is given the test and tests positive, what is the probability that the person actually has the disease?

5. Which of the following is more probable:
correctly guessing all the answers on a 20-question true-false exam
flipping a coin 20 times and obtaining all heads
correctly guessing all the answers on a 10-question multiple-choice exam that contains five choices for each question
Support your choice with appropriate reasoning. Please give explanation thats the most important thing for me

2007-12-05 17:26:30 · 3 answers · asked by Anonymous

I need help on solving multi step equations can you please help me here's an example
m+12 over 9m = 5 over 9
sorry i cant do fractions on the computer and also how do you check it to see if its right

2007-12-05 17:25:10 · 5 answers · asked by Ck23 2

example would be

x+4/x-6 is less then or equal to 0

well i get the answer as (-4,6) but i know the need for brackets is in there because its an equal to question, which number do you know to put the bracket on or is it both? please help and thanks!

2007-12-05 17:21:17 · 5 answers · asked by bfcookie2002 3

2007-12-05 17:15:30 · 1 answers · asked by Anonymous

A laboratory sample consists of a mixture of two radioactive substances, both of which decay into inert gases which evaporate into the air. The initial composition of the sample by weight is 20% of substance A and 80% of substance B and the initial weight of the sample is 264 grams. After 2 days the sample weighs 217.612240257459 grams and after 4 days it weighs 179.666588758521 grams.
a) What is the half-life of substance A?
b) What is the half-life of substance B?
(c) What will the sample weigh after 25 days?

I'm confused about how to deal with the 2 substances in the sample, so I don't even really know where to start with this one.

2007-12-05 17:12:46 · 2 answers · asked by Laura 1

make LHS = RHS
cos(x+y)cosy + sin(x+y)siny = cosx

I expanded both cos(x+y) and sin(x+y) then expanded again, and that's where I'm stuck, was I even suppose to expand again?

Please provide a full solution, thanks!

2007-12-05 17:10:13 · 4 answers · asked by fye 1

The problem reads: " For vector v = (-3,4), graph the vector, compute its magnitude and find the angle of the vector and the nearest x-axis.

I drew a picture and used a parallelogram to help solve for the magnitude and angle of the vector and the x-axis.

I got a magnitude of 5 for v and the angle of v and the x-axis is 53.1 degrees.

If anyone could check this over I would greatly appreciate it!

2007-12-05 16:48:16 · 4 answers · asked by No Doubt 1

2007-12-05 16:42:51 · 3 answers · asked by Anonymous

2007-12-05 16:35:18 · 3 answers · asked by bizzy11lizzy 2

i am trying to figure out how to figure $245.99 with 40% off....how would i do that on a calculater? And how would i figure it out with different numbers?

2007-12-05 16:30:26 · 21 answers · asked by Anonymous

did sat. they sold 82 boxes of cookies fri. how many boxes of cookies did they sell sunday?
show me how you get the answer and why u took this steps to solve

2007-12-05 16:26:23 · 3 answers · asked by stephanie k 1

Having lost all of our money and Mr. B losing his job, we wallow in our disappointment as we head over to the lounge to listen to some Elvis impersonator - hey, at least it's free. There on the table is a handout with the different parlay cards on it. We take the $5 bill off the table that the last people left for the cocktail waitress and place a bet. What is the best bet to make on the handout - assuming we are going to make a bet? If you get it right we will win big money, save the day and have enough to give Mr. B enough money to buy the school board and get his job back. Show all work (except unnecessary work) and give explanation- assuming a smart person is looking at the parlay cards.

Thank you so much for your help!!!!!

2007-12-05 16:22:33 · 2 answers · asked by Jared D 1

Betty's diner makes 15% profit on its lunches and 22% profit on its dinners. If the diner took $2700 on Tuesday and made $524 profit, how much was spent at lunch? Let x represent the sales at lunch and y represent the sales at dinner, write two equations, then solve.

♥Thanks♥

2007-12-05 16:20:42 · 1 answers · asked by liz! 3

10x^2-3xy^-y^2

2007-12-05 16:19:31 · 2 answers · asked by Ebony N 1

y = sin(pix/2) and y=x?

so i know one of the steps is to solve x

sin(pix/2) = x
im not sure how you would solve for that.


i know after you find the intersection points you would find a number in between [a,b] that would tel you which of teh two y's are bigger.

then you fine the area by taking the integral of the bigger-smaller and then taking the derivative of that and solving F(b)-F(a) but i cant do anything without knowing the values of x and i just dont know how to solve with sin in the problem

2007-12-05 16:10:33 · 5 answers · asked by Anonymous

Find the antiderivative

⌠ 8x / √(x^2+2)
⌡

2007-12-05 16:09:42 · 3 answers · asked by Rachel 1

When 30 orange are planted per acre each tree yields 150 oranges For each addtional tree per acre, the yield decreases by 3 oranges per tree. Express the total yield of oranges per acre, Y, as a function of the number of trees planted per acre, x, if x>/= 30.

Please help me explain the answer is Y=240x -3x^2. How do you get that?

2007-12-05 15:59:54 · 1 answers · asked by Andrewjoe 1

given: ABCD is a parallelogram, line ABE, angle CBE is congruent to angle CEB.
prove: a. angle DAE is congruent to angle CEA
b. AECD is an isosceles trapezoid
i have a lot of problems with proofs; i really dont understand. any help would be greatly appreciated, thank you!

2007-12-05 15:56:38 · 4 answers · asked by redx 2

what is 80% less than 800?

thank you!!

2007-12-05 15:55:37 · 3 answers · asked by Anonymous

2007-12-05 15:54:21 · 1 answers · asked by xtmilx 2