I need help with math

2009-01-19 02:21:46

#1

Bradt3hleader: Care [ ] - Don't care [x]; +121|6362

Hey guys,

In school we've been working on something with letters, like (3x+2)(3yx-9z). I don't know what it's called in English. But anyway I googled it and I can't find any good sites that explain it properly. The example I showed you is easy, but I don't know how to make the square root signs and to the * power signs with a keyboard. And those are the ones I'm having trouble with.

Does any1 know a good math site that properly explains everything with this category of math?

2009-01-19 02:32:21

#2

Gawwad: My way or Haddaway!; +212|7111|Espoo, Finland

I'm sure you can get a good explanation here.
Use sqrt for square root.
sqrt(3x + 2) is squareroot of 3x + 2

Have you read the examples and theory in your school book?

Last edited by Gawwad (2009-01-19 02:32:53)

2009-01-19 02:41:02

#3

Bradt3hleader: Care [ ] - Don't care [x]; +121|6362

Well they're pretty cheap, quickly written, and our teacher made us correct a few mistakes in the book. So it's not very good stuff, besides french isn't my first language even though I speak it fluently I still think it makes no sense with all it's "Celui-ci and celui-la"s...

I just want something that explains the rules properly and make it simple. As through my experience learning, nothing has ever been difficult if tought properly.

2009-01-19 02:46:24

#4

liquidat0r: wtf.; +2,223|7053|UK

I'm not entirely sure what you're asking. But I'm willing to help.

When typing, to represent the square root of a number, you just type sqrt(number). This, or similar, is what is used in most programming languages and things like Microsoft Excel.

As for indices (powers) people normally represent them like this:

x^2 = x squared
x^3 = x cubed
x^(4x+3) = X raised to the power (4x+3)

On some forums, namely this one, you can use BBCode to represent powers. For example:

y = 3x³ - 9x² + x - 2

Code:

y = 3x[sup]3[/sup] -9x[sup]2[/sup] + x - 2

2009-01-19 02:55:17

#5

Bradt3hleader: Care [ ] - Don't care [x]; +121|6362

Ok thanks, now I got the keyboard thing down.

Right well I'm doing some extra math papers I asked for so I don't flunk the semester, although it's too late And the big problem with the things without all the square routes is I get lost...in things like 4a²b - 2a³ + 6a². Indices are shit...

How do I do that? I never know what to do with the indices

Last edited by Bradt3hleader (2009-01-19 02:56:53)

2009-01-19 02:56:52

#6

liquidat0r: wtf.; +2,223|7053|UK

Can't help you unless you give us an example of an actual question, rather than just stating examples of things written on the paper.

2009-01-19 03:00:23

#7

Bradt3hleader: Care [ ] - Don't care [x]; +121|6362

I'm just so mixed up now I don't even know what I'm doing, homework+forums+cooking at the same time = fail...

Here are some of the big problems...

4a^2b^3 - 2a^3b^2 + a^2b^2 + 6a^2b^2 = OMG WTF?

a^b^2 - a^2c^2 - b^4 + b^2c^2

BTW thanks alot in advance!

EDIT: oh and I have 4 pages of these problems...so I just want to see how you develop, organize and factorize or whatever please.

Last edited by Bradt3hleader (2009-01-19 03:01:05)

2009-01-19 03:07:02

#8

liquidat0r: wtf.; +2,223|7053|UK

Yeah but what are you supposed to do with them?

Assuming the first one is this:

y = 4a²b³ - 2a³b² + a²b² + 6a²b²

You can take a²b² out of every term, so:

y = a²b²(4b - 2a + 1 + 6)

But yeah, not sure what you're supposed to do.

2009-01-19 03:13:20

#9

Bradt3hleader: Care [ ] - Don't care [x]; +121|6362

it says "Factorise ces expressions au maximum" so that means factorize these expressions to the maximum.

edit: Meanwhile I'm looking at youtube stuff and math sites for this...

Last edited by Bradt3hleader (2009-01-19 03:14:47)

2009-01-19 03:17:43

#10

liquidat0r: wtf.; +2,223|7053|UK

OK, so the second one:

y = a²b² - a²c² - b⁴ + b²c²
y = a²(b² - c²) - b²(b² - c²) ---> Here I factorised a² out the first two terms and b² out of the second two
y = (b² - c²)(a² - b²) --> Here I factorised (b² - c²) out of both terms

Sorry if I've made any mistakes.

2009-01-19 03:30:25

#11

mcminty: Moderating your content for the Australian Govt.; +879|7148|Sydney, Australia

Brad, don't think anyone has said.. but this stuff is (edit: basic..) Algebra. Post some more questions you are having trouble with.

What grade/year of school are you in?

2009-01-19 05:13:54

#12

Bradt3hleader: Care [ ] - Don't care [x]; +121|6362

9th grade, switzerland. I own every1 at anything else, but I should be sent back to kindergarden algebra

Next year I'm starting my computer programming school, it's 2 years of hardware and software and troubleshooting then 1 year of programming, we'll see what I do after that.

Now alot of algebra involved in that right? Doesn't matter, I refuse to finish this year not being able to get past this stuff.

EDIT: TBH, I think I'm just gona go and get that first book of all the basics out, and study that alot.

Last edited by Bradt3hleader (2009-01-19 05:15:16)

2009-01-19 05:16:13

#13

Finray: Hup! Dos, Tres, Cuatro; +2,629|6215|Catherine Black

You mean maths, amirite?

2009-01-19 05:17:10

#14

liquidat0r: wtf.; +2,223|7053|UK

I find it difficult to believe that you're good at everything else if you can't do basic algebra. Seeing as the majority of mathematics relies on a decent understanding of algebra.

2009-01-19 05:19:37

#15

AussieReaper: ( ͡° ͜ʖ ͡°); +5,761|6579|what

Bradt3hleader wrote:
9th grade, switzerland. I own every1 at anything else, but I should be sent back to kindergarden algebra

Next year I'm starting my computer programming school, it's 2 years of hardware and software and troubleshooting then 1 year of programming, we'll see what I do after that.

Now alot of algebra involved in that right? Doesn't matter, I refuse to finish this year not being able to get past this stuff.

EDIT: TBH, I think I'm just gona go and get that first book of all the basics out, and study that alot.

Yeah, you will actually have a lot of algebraic equations when you do start your programming. During my IT degree I've had to fall back on a lot of my mathematics from high school that involved factorising.

The main type you'll find that used will be during say programming a search\sort algorithm.

Make sure you really do understand exactly this sort of maths.

edit:

Here's some of the programming you'll do involving these algebraic equations:

http://math.hws.edu/TMCM/java/labs/xSortLabLab.html

Not every sorting algorithm is an N2 algorithm. Some of them are N*log(N) algorithms. This means that the running time of the algorithm is given approximately by K*N*log(N), where N is the size of the array and K is a constant. The function log(N) is the logarithm of N. You can compute this function using the "log" button on your calculator. (There are actually many different logarithm functions, and you can use any of them as long as you are consistent. If you use a differernt logarithm function, you'll just get a different value for K. The log function on your calculator is almost surely the "common" or "base-10" logarithm, and that's the one that I will use in this lab.) You don't need to know anything about logarithms, except that when N is large, N*log(N) is much smaller than N2. This means that for large values of N, an N*log(N) algorithm will run much faster than an N2 algorithm. Based on this, you can probably guess which of the five algorithms are N2 algorithms and which are N*log(N) algorithms.

Of course, you can use the measurements you made in the previous section of the lab to compute an approximate value for K. If T is the time it takes to sort an array of size N, then an approximate value for K is given by the formula:

K = T / (N*log(N))

Last edited by TheAussieReaper (2009-01-19 05:23:49)

2009-01-19 06:38:12

#16

Metal-Eater-GR: I can haz titanium paancakez?; +490|6699

I dont see the deal here?
Where is your problem in factorising expressions? I think liquidator has covered it pretty well above.

Take this example
(Lemon x Orange) + (Lemon x Apple) + (Lemon x Cherry)
Lemon being the common "fruit", in those three terms=
Lemon x (Orange+Apple+Cherry)

I cannot explain it otherwise. I aint a frikin maths teacher :p

2009-01-19 07:54:54

#17

Bradt3hleader: Care [ ] - Don't care [x]; +121|6362

ok well thanks guys, looks like I just fail at this and should restart from blank... thanks alot for the help though...

2009-01-19 10:12:47

#18

Ryan: Member; +1,230|7269|Alberta, Canada

Your grade 9 algebra is way more complicated than my grade 11 stuff.

2009-01-19 10:33:05

#19

JoshP: Banned; +176|6115|Notts, UK

how old are all these grade things?

I'm in the last year of sixth form (17-18 years old unless you cheated and skipped a year like me) and the stuff is advanced...

but still easy

2009-01-19 11:04:54

#20

Ryan: Member; +1,230|7269|Alberta, Canada

JoshP wrote:
how old are all these grade things?

I'm in the last year of sixth form (17-18 years old unless you cheated and skipped a year like me) and the stuff is advanced...

but still easy

I'm in grade 11, which has kids with an average age of 16 to 17.

I'm turning 17 in February, and I'll still be in grade 11.

2009-01-19 11:07:39

#21

JoshP: Banned; +176|6115|Notts, UK

Ryan wrote:
JoshP wrote:
how old are all these grade things?

I'm in the last year of sixth form (17-18 years old unless you cheated and skipped a year like me) and the stuff is advanced...

but still easy
I'm in grade 11, which has kids with an average age of 16 to 17.

I'm turning 17 in February, and I'll still be in grade 11.

That's like our Year 12
What do you do in maths?

2009-02-04 15:55:38

#22

Sheen1101: Member; +12|7046

I need help on one calculus problem and searched the forum and found this one and thought what the hell I'll post it here, so the question is:

Find the limit. When x approaches infinity. At first I thought the answer was negative infinity and it's not so I'm like wtf what is it? help?

lim(x --> infinity)(x + √(x² + 9x))

2009-02-04 16:17:57

#23

Peter: Super Awesome Member; +494|6828|dm_maidenhead

Surely it just goes towards infinity. Assuming the positive square root is used from the + in front of it. It is all adding and multiplying so it just tends towards infinity doesn't it?

2009-02-04 16:28:51

#24

Sydney: 2λчиэλ; +783|7270|Reykjavík, Iceland.

Definitely infinity, there is no reason for it to go negative, all the powers are positive, and nothing is being divided by x.

As you can see here
http://rechneronline.de/function-graphs/

by putting in

Code:

x+(x^2+9x)^0.5

You see that when x goes to infinity, so does y

2009-02-04 16:29:09

#25

argo4: Stand and Deliver; +86|6359|United States

Sheen1101 wrote:
I need help on one calculus problem and searched the forum and found this one and thought what the hell I'll post it here, so the question is:

Find the limit. When x approaches infinity. At first I thought the answer was negative infinity and it's not so I'm like wtf what is it? help?

lim(x --> infinity)(x + √(x² + 9x))

when i graph it, it looks like +infinity

BF2S Forums I need help with math

Code:

Bradt3hleader wrote:

JoshP wrote:

Ryan wrote:

JoshP wrote:

Code:

Sheen1101 wrote:

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