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Author Topic: To: All who missed the last math thread
wieczorek
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I have another question concerning math and if anyone feels up to it, you are most welcome. Disappointingly, it's not very involved and won't take hours to produce a post on it, so I offer my apologies before hand... [Wink]

Can anyone describe to me how to go about solving an equation with "gamma" in it? I'm taking Algebra II and I don't take calculus, but I need knowledge of some of it for a project. Take this for example:

99-(square root of 9 ) - gamma - (square root of 9 )

How would you go about solving this? Does gamma have a fixed value? I would suppose not, but...what is its value when expressed with variables and/or numbers? [Dont Know]

If anyone knows, I would greatly appreciate your help. [Smile]

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dspeyer
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I don't understand: you have no equals in your equation. (Or < or > and so on.) Your equation is like saying "Flour mixed with eggs." and thinking that you have a sentence because "mix" is a verb.

Similarly, if you just give me numbers, arithmetic operations (+, -, *, /) and a variable, I don't know what it means to solve this.

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Rappin' Ronnie Reagan
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Dude, you're in algebra II and you're doing stuff with gamma? I went through Calculus AB and I have no idea what the hell that is. I also couldn't understand your last math problem. Does that reflect poorly on me or my teachers?
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saxon75
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I'm pretty sure he means that he wants to evaluate expressions with gamma in them, not necessarily solve equations.

Not that I'm any help for that.

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Paul Goldner
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Gamma is often the expression

1/root (1-v^2/c^2)

but it doesnt' look like it from that [Smile]

You need to tell us what gamma is in this situation.

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wieczorek
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quote:
I'm pretty sure he means that he wants to evaluate expressions with gamma in them, not necessarily solve equations.

That's more precise - sorry, I should've said "expression", not "equation". [Blushing]

Perhaps I should say that I need to know how gamma functions in any situation, so that I can then evaluate an expression that contains gamma. Sorry if I wasn't clear - [Big Grin]

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Morbo
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Rabbit already defined gamma in your previous thread.
"gamma(x) = integral from 0 to inf of t^(x-1) exp(-t) dt.

The gamma function interpolates the factorial function. For
integer n, gamma(n+1) = n! (n factorial) = prod(1:n)."

or gamma(m)=(m-1)!=(m-1)*(m-2)*(m-3)*...*3*2*1 for integer m.

It's fairly obscure, you won't use it until calculus and even then only once or twice if ever in high school level calc.

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Richard Berg
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Gamma has a few standard meanings in pure math. There's the module group that's impossible to explain unless you know some modern algebra; there's the function that (among many other things) generalizes the factorial operator to complex numbers; there's the Euler-Mascheroni constant that can be used to compute the gamma function as an infinite product; and there's the distribution in statistics that's related to the common Poisson distribution but can be computed from the gamma function. There are tons of physics connotations -- here are a few. I give these as teasers for the math-heads in the audience, as I highly doubt any of it has to do with your high school homework.

Assuming you've stated the problem correctly, I would evaluate the expression*
as "93 - γ".

*remember the difference between this and solving an equation from pre-algebra?

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wieczorek
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quote:
It's fairly obscure, you won't use it until calculus and even then only once or twice if ever in high school level calc.
Morbo, something sporadic can be good... [Big Grin]

quote:
*remember the difference between this and solving an equation from pre-algebra?
Two years ago I took advanced algebra, and geometry and trig last year, so I wouldn't remember that - j/k. Yes, I remember that from the last few years of math, but it slipped my mind at the moment [Wink]
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Noemon
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Of courese, "Flour mixed with eggs" could be a legitimate sentence.
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BannaOj
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Is it a capital Gamma or a small Gamma. I know some funky contstants that use a little gamma from physical chemistry, but I think you probably want the capital Gamma which I never used until my second semester of differential equations which would be in my sixth semester of college level math. I vaguely remember that it has something to do with the heaviside function.

AJ

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Zan
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gamma is the unit weight of soil (or dirt for you non-technical types).
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BannaOj
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OK you can find the Gamma function explicitly defined in the table of integrals in the CRC handbook of chemistry and physics. I would reccommend looking it up yourself because it is hard to type it correctly. In my old edition it was integral #597. They also have a more complete definition if you look in the index under "gamma function"

It is the solution of the integral from zero to infinity of x^(n-1)* e^(-x) dx

One of the more useful properties:
Gamma(n)= (Gamma(n+1))/n

Also Gamma (1/2)=sqrt(pi)

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dspeyer
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Well, if it is a capital Gamma and then the square root of 9 is right after it in parenthesis, meaning "Gamma of square root of 9" then that makes sense.

For any positive integer k, Gamma(k)=(k-1)! so in this case Gamma(SquareRoot(9))=Gamma(3)=(3-1)! and you can finish the computation from there.

I tend to doubt this would show up in an Algebra class without calculus though. In general, the gamma function is like the factorial (shifted by one) in that Gamma(x+1)=xGamma(x), but that formula is useless without some sort of starting value (analogous to 1!=1) to compute from. As the rabbit posted, you can define Gamma by:

Gamma(x)=integral_0^infinity e^{-t} t^x dt/t

and then it is a nice excercise to prove by integration by parts that this gives Gamma(x+1)=x Gamma(x).

I know a few other definitions, but they all need calculus. Has your teacher een talking about factorials or gamma at all?

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Dan_raven
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I thought Gamma rays were what turned Bruce Banner into the hulk.
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luthe
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More About the Gamma Function than anyone should need to know
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Morbo
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Thanks, luthe, that link led me to a generalization of the factorial function which I had never heard of, the double factorial n!!
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HollowEarth
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what are you doing in algebra 2 that you need the generallize the factorial for?

The first time i did stuff like that was with the statitically thermo in pchem 2. which was like spring of my sophmore year of college.

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Morbo
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Wieczorek is in high school. My high school days are a distant memory. He was looking for weird real functions to do a homework problem, someone suggested Gamma.

I don't ever remember using Gamma in years of pursuing a BS in math, except once or twice in a problem set.

[ October 03, 2003, 07:01 PM: Message edited by: Morbo ]

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larisse
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luthe,

I know you warned us about that link, but really.... WARN A PERSON about that link. Sheesh! Doing this => [Wall Bash] is much more enjoyable.

On the weird side... is it just me or do those graphs bring to mind "... making mountains out of molehills". Okay... it's just me.

Of course this is also just me, but math is really pretty when it's not doing stuff with numbers. [Big Grin]

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wieczorek
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Morbo's correct, Hollow Earth. There's a thread called, "Has anyone heard of this? ENTER AT YOUR OWN PERSONAL RISK". Alot of people contributed to it - I had a project and my teacher suggested using factorial. I think it was Rabbit who first suggested using gamma.
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wieczorek
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Thanks, Luthe. That link will help me justify my use of gamma that I so willingly assumed without having knowledge of its function. [Wink]
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Morbo
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Larisse, you're right, those graphs are pretty, especially the 3-D ones.
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