Science & Mathematics - 30 January 2007

I cannot figure out how to display this numerically, someone pls help.

A (1.3) B(5,7) C(4,8) and D (a,b) form a rectangle find a,b

Now I have come up with so far the rules, that if it is a rectangle then AB and CD must be parallel so gradient AB = gradient CD which has left me with

(7-3) 8-b
------ = ------
5-1 4-a

4/4 = 8-b/4-a

Now I know here that obviously b is 4 and a is 0, but from the above a could equal 2 and b could equal 6 for all the layma knows

So then i went and said, for it to be a rectangle AB must be perpendicular to BC, I found ab gradient to be 1, so therefore BC gradient must be -1 and as a result

So therefore I said that 7-3/5-1 * b-3/a-1 must equal -1

therefore 1* b-3/a-1 must equal -1.

Now the only number that multiplies 1 to acheive -1 is -1

so b-3/a-1 = -1

but i have no idea where to take it from here, do I form a simualtaneous equation to work the rest out or what??

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I have heard this even applies to like the number of female bees to male bees in a hive, or the ratio of the number does. Does anyone else know anything?

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Our grating is from a Frey Scientific cat.no.17912, and the package says they have 500 lines/mm. For some reason, from the angle that we are getting by shining a red laser pointer through, we are calculating the wavelength of red light to be almost twice as much as it should be. What's going on?

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The sampling distribution of x(bar) has standard deviation sigma/squareroot(n) even if the population is not normally distributed. Is this true?

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examples are: bobcats, wildcats, tigers, pumas, cougars, etc.

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5 times the square root of 5 SUBTRACT 4 times the square root of 3

ALL THAT under 1 (as a fraction)

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need to know how to do this for a test

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I would like to know just a common list of poisons?
Please and thank you gloria

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hey can any of you guys recomend were to go to find this?and also to find a picture of it?

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Such as:
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or anything else easy.
A few days ago my teacher told my class to dicesect an owl pellet.
Although, it smelled rotten as rotten as like i was sick to death.
He said next we will start off with starfish.
Do u remember doing anything fun in biology class?

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a very very large mass can warp space and time, right? is that because of the relatively strong gravitational pull it exerts?

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This question is for chemistry

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p=psxe^-z/H
p=(ps/RT)xE^-z/H
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ps=surface area
R-gas constant
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Here's the problem:

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