Math

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I am VERY bad at maths. Yet the annoying thing is I am in a high maths class at school as for some reason I always get very high grades on the tests, but I can never understand the classwork. So could someone explain how some things work for me please?

Like where Noblemen said his age is 7.5 divided by 1/2 = 10. The answer is 25, but I don't get how to work that out, any help?

I'm fine with Ratios and get by with Algebra, but questions like these, i just don't get...

Thanks,

-Z- (failing as standard )

[ September 17, 2002, 20:20: Message edited by: Z-Layrex ]

 

dividing by half is like multiplying by 2

7.5/0.5+10
= 7.5 x 2
= 15
~ 15 + 10
= 25

 

Ah i get it.

Thanks alot 8people. If i get anymore i'll post them.

 

And multiplying by a half is the same as dividing by 2, pretty much the same, but backwards.

It's easy once you getthe hang of it.

No, really, it is!

Frosty
(Actually likeing maths)

(Hey get this straight-jachet off me, what have I done?)

 

you can look at numbers as apples. Division can be split up into two situations. one where you divide with a fraction and one where you divide with a whole number. If you understand both methods, you can do any kind of arithmic division.

Method one. Whole numbers
You have two apples and is asked to divide them by two. This means you have to make two piles and put equal amount of apples in each pile. Hence you have two apples for two piles, thus the result would be 1 apple in each pile. The mathematical expression would be 2/2 = 1

method two.
You have two apples and is ordered to divide by 1/2. Now all you do is to imagine cutting the apples in half. How many pieces do you have? 4 right. In method two, when dividing with fractions there is only one pile which grow larger according the the size of the fraction.

Harder example.
Now you have 12 apples and should divide them by 1/4
The way to go, is to imagine cutting the apples is four pieces each. so 12 apples which each are cut in 4 pieces, gives us 48 pieces. Remember just one pile, when dividing with fractions. The mathematical version would be 12 / 1/4 = 12 * 4 =48

In the last example we have 12 apples and divide them by 2/3. Whats the way to go? If we combine the methods we'll get the answer.
Now as seen in method 2; 12 apples split in three pieces each gives us 36 pieces in the pile. Now all thats left is to divide the 36 apples in 2 equally large piles(method 1).this gives 18 apple-pieces in each pile. The mathematical version is:
12 / 2/3 = (12 * 3)/2= 18

If you can figure out 12 divided by 4/3 youl'll be able to answer anything in household division.

[ September 17, 2002, 21:12: Message edited by: Nobleman ]

 

Great, thanks alot it's alot clearer to me now Noblmen. You'd make a pretty good maths teacher you know.

 

Or you can just say:

Divide by a number greater than 1 the answer decreases
Divide by less than 1 it increases

Or
A fraction, dividing by half
1
-
2 <-- This is the number you use. Use it to times

Multiplying is to divisions as addition is to subtraction

multiply by more than one the answer increases
Multiply by less than one the number decreases

timesing by a fraction is just adding the fraction of the number onto it, IIRC Yeah, but some may not understand my wording, I'm not one with words, unless in creative writing

 

Thx. I have editted out all the bad grammar. Should actually be more understandable now

 

umm...
This topic messed my head.
I am usually good at math but this...
/me walks out thru the door...too bad it was a window and she is standing on the 7th floor.

 

OMG! A whole bloody bunch of math teahers! The world is at an end!

 

This is easy. Don't they teach you in high-school that multiplying by a number is the same a dividing through the opposite of that number?

Addition and substraction is the same.
Multiplying and dividing is the same.

[ September 18, 2002, 18:47: Message edited by: Silverblade ]

 

I learnt that in year 3

 

Look, there's no reason to make fun of me you two.

 

Perhaps you're a natural 8people. Here is a great assignment from calculus. If you can do it, you'll make me thrilled

solve the equation X^X^X^X... = a where a>0
The exponent tower goes on forever.
A really fun one.

EDIT; And don't tell me you knew that at year 3

[ September 18, 2002, 19:21: Message edited by: Nobleman ]

 

I'm not making fun of you Z

I was just poining saying that i learnt that when I did, I find maths easy as I find visual stuff easy to understand

Like in clas we're doing equations and brackets and stuff and if you get mixed up with adding and subracting in it it can take three attempts until you realise you've gone wrong

 

I know exactly how you feel, Eilonwy. I used to have this huge mental block against algebra. I actually took it, and failed it, five (5) times! Then, when I learned that to study biology I had to take math through Calculus 2, I realized that I somehow had to pass. So I memorized everything -- I didn't understand it, not at all, I just memorized it enough to spit it back out. (Got an "A.") When I got to Calculus, all that algebra FINALLY MADE SENSE. The scales fell from my eyes! I can't even tell you now what had been so hard to understand, because I know it like I know my name.

And brilliant explanation, Nobleman -- I love the apples.

How about a=1?

 

Mrethylviolet:

a=1 is a simple case, no? But you need to solve for x...

I have been trying to form a recursive infinite series (A(n), A(n-1) etc, where A(n)=x^x^x...x -n times) and then ln-ing it and going for lim->inf, but no luck so far.

Nobleman: are you sure there is an analytical solution to this?

-thanos

 

It is a bonus assignment we were given. Just to make your soul peaceful Thanos; it isn't easy. But it has a certain simplicity. Just wanted to test 8peoples skills. It would be wonderfull to see a shining new mathematician rise.

 

Well, to make my soul peaceful, I haven't touched infinite series stuff (if this is indeed what the soultion is), since 1994 (1st year in university).

On the flip side, give me a Fourier (or z, or Laplace) transform over that stuff any day

-thanos

 

I thought it was self-explanatory that if a=1, then all your x, yes, to infinity, are also 1. If there is another number not 1, then search me.