Math Is Fun Forum

Well, by using the "absolute value" function abs(), you can use:

abs(x) - x^2   (absolute-value-of-x minus x-squared)

When I tried this on our graph plotter, I found it looked best using 2*abs(x)-x^2

Correct, amber, and we have some examples of reflex angles here

Well, we do have some simple explanations of fractions starting at Equivalent Fractions - look for the links at the bottom of the page for lots more about fractions.

Likewise you can check out Percentages and also do a short Percentage Test

OK, I believe we can look at the problem like this: we want to know the difference between two successive n-values for any w (this difference will be the "D" value mentioned in your questiom)

First let's expand out the function: 1+4w(1+w+n) = 1+4w+4w^2+4wn

Let us see what the difference between two n-values is (call them n_1 and n_2)

   1+4w+4w^2+4wn_1
- 1+4w+4w^2+4wn_2
= 0+  0+       0+4w(n_2-n_1)

= 4w(n_2-n_1)   

So, that would be the solution for one difference "D" (remember the D_n = D_(n-1) + D_(n-2) formula?)

Let us try to "plug this into" that the D_n = D_(n-1) + D_(n-2) formula. For ease of writing this on the screen I will use actual numbers, but you can substitute (n-1), etc:

4w(n_3-n_2) = 4w(n_2-n_1) + 4w(n_1-n_0)

simplifying:
n_3-n_2 = (n_2-n_1) + (n_1-n_0)
n_3-n_2 = n_2-n_0

And that last formula is indeed a Fibonacci sequence which we can prove by playing with it:

substitute n_2 for n_2=n_1+n_0

n_3-n_2 = (n_1+n_0)-n_0

Simplifying:

n_3-n_2 = n_1

or
n_3 = n_2 + n_1

So, I have "shown" how this can be proved. You just need to neaten it up a little before calling it a proof, OK?

Hi Rabid, is the language Visual Basic?

Perhaps the problem is that the value is text, not numeric. Try converting it first. In VB you could use CDbl().

Also try showing the numbers before and after the calculation (debug.print or msgbox or whatver works to show them on the screen) to see what is going on.

It is also possible that when dividing by 100 it is thinking "this is a whole number, so the answer should be a whole number".

Try this:

MinDeposit = cdbl(txtPriceOfProperty.Text) * 0.05
if (Deposit >= MinDeposit) then
...
end if

Let's know how you get on

The Fibonacci sequence follows the simple rule of adding the previous two numbers to get the next.

0,1,1,2,3,5,8,13,21,34, etc

That is stated in your problem as D_n = D_(n-1) + D_(n-2) (for example, 21=13+8)

Now, trying to decipher the problem, I believe it is saying that when calculating the formula 1 + 4w(1 + w + n), where n follows a fibonacci sequence, the difference between each successive answer also follows the fibonacci sequence.

Let's plug in some real numbers to get an idea of this.

Let us try w=3:

n    T_n   Difference
0      49    
1      61    12
1      61     0
2      73    12
3      85    12
5    109    24
8    145    36
13   205    60
21   301    96
34   457   156
 
So, we have n following the Fibonacci sequence, we have calculated 1 + 4w(1 + w + n) for w=3 and different values of n, and we have calculated the difference. Interestingly, the difference also follows the rule that the previous two numbers add up to make the next. (12+0=12) (12+12=24) etc

If you believe I have stated the problem correctly, please let me know, and we can then work on the proof.

That is a great avatar, eurasiangurl.

I used to teach at Uni. I can't give you one-on-one help, but feel free to post any questions and I or another member can respond. That way other people get to the chance to see questions and answers, or perhaps to correct me if I am wrong!

A 3D cube is just a simple box. So it has a top and a bottom, a front and back and a left and right side. In othe words just 6 sides. But if you count the edges, there are 12.

You can find out more here: Platonic Solids

Hi Deepak.

Most of what you want is available on the internet at different locations, but if you could buy a book or two that would really help, because you can study the book, and then use the internet for further research.

This is only a suggestion, but I think you could narrow down your studies, instead of learning all of 12th standard, try to dicsover what specific areas you need to know more about, and focus on those.

Not a problem, eurasiangurl, here is another:

To solve algebra, you just have to move things around until it works out. A bit like a puzzle:

Let's try Problem No 56:
y(y+11)=0

Let's expand it out a little:
y times (y+11) =0 can be turned into:
y times y + y times 11 =0
or:
yy + y11 =0   , this is NOT the right way to write it down! so we will correct it to:

y^2 + 11y =0  (where y^2 means y-squared, or simply y times y)

Now, subtract 11y from both sides to get:
y^2 + 11y - 11y = 0 -11y
simplify it:
y^2 = -11y

Now, divide both sides by y:
y^2 /y = -11y /y
simplify:
y = -11

TA DA!

Just to be safe, let's check it:
y(y+11)=0
substitute "-11" for "y":
-11 times (-11 + 11) = 0
-11 times (0) = 0
0=0

Great, we got it

If there was a part of this you didn't follow, let me know.

tell us what you are having trouble with - long division? algebra?

It took me ages, too ! And 3 goes, and lots of paper.

I found that writing their names in the right order (left to right) helped, so Lucy is first because it says she is on the left, and Georgina is last, and I could figure that Hannah is in the middle because she likes Dairy Milk and Dairy Milk is in the middle. That gave me a good start.