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Type I -- Infinite Summation


ballon

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No need. If cdrom uses Ms.Excel they could just show the equation from Excel. I guess it's just the same but you are not supposed to reveal the answers.

The example can be used because it's just telling us what they mean by Tn(a,x). They gave an example to prevent misunderstanding as sometimes some slow people (like me :S) just won't get it.

i've been using my calculator because i'm not very good at formulas in excel, however i have been using excel to make my graphs (i've had to copy in all the points and create a graph.......verrrrrrrry tedious)

By term I meant the each term for each value of n. The sum (Sn in the first part and Tn(a,x) in the 2nd part) is the sum of each term until a value of n.

Sn or Tn(a,x) = t1, t2, t3, ..., t(n-1), tn :P

Are you clear with that?

yes! i get that

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i've been using my calculator because i'm not very good at formulas in excel, however i have been using excel to make my graphs (i've had to copy in all the points and create a graph.......verrrrrrrry tedious)

If you use a TI calculator, it's actually better to use it to make the graph, because excel is sometimes not good enough to plot data and generate some types of functions. Do you have the software? So that you can just take a screenshot and paste it in your portfolio :P if you use TI, tabulate your data, and then plot it. If you don't know how, read this post XD just ignore steps 8-10, though :S

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why is it, that when you take the logarithm of a number between 0 and 1, you get a positive number, and then a negative number, and then a positive number and then a negative number and so on?! i need to explain this in a part of my portfolio, and i have no idea...!

What do you mean?

Let y=log(x)

when 0<x<1, y<0 (is negative)

when x=0, y=0

when x>1, y>0 (is positive)

Plot y=log(x) to see more clearly.

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What do you mean?

Let y=log(x)

when 0<x<1, y<0 (is negative)

when x=0, y=0

when x>1, y>0 (is positive)

Plot y=log(x) to see more clearly.

i mean that when i have an 'a' value of 1/5, the values i get for Sn, I get (look at screenshot)

and the same thing happens when i have cos(0.08).

so i need to explain why every other value is a negative number..

post-46031-0-95540400-1298220677_thumb.p

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i mean that when i have an 'a' value of 1/5, the values i get for Sn, I get (look at screenshot)

and the same thing happens when i have cos(0.08).

so i need to explain why every other value is a negative number..

oh the 'a' value. I see. I'll get back to you tomorrow :lc:


Can anyone suggest a good graphing program to use, besides Excel and GeoGebra?

Or can someone please explain to me how to draw lines connecting the points on GeoGebra??

Use your TI calculator :)


In reference to the format, are we required to keep all answers correct to 6 d.p., or only the first part, calculating Sn?

I think it's up to you but I would keep giving all answers with 6 d.p. for the sake of consistency :)

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Really this isn't actually a difficult Type I portfolio. I just finished this like 1 month ago and got 19/20 (teacher mark) on it. I'm telling you this (don't know what I'm supposed to tell you): It isn't that complicated, just do it naturally. However, the "wow" factor for this portfolio is algebraically coming up with a^x (which is higher level maths but it's still possible if you can work you're way around it).

P.S: Derivates and Taylor Series are two key methods.

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hey im really, very stressed about this IA and its due tomorrow for me.

for the first part, what is the general statement/formula? how do i find it or even explain it? im so confused and when i stress out i cant focus.

your help would be appreciated XD

I'd suggest you read the whole thread first, for it has A LOT of vital information about the whole I.A. . . I have recently done this, and my posts and questions which might help you will be there as well, so feel free to browse through the thread first, if you can't seem to find what you are looking for, just tell us, and we will answer your question directly...

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I'd suggest you read the whole thread first, for it has A LOT of vital information about the whole I.A. . . I have recently done this, and my posts and questions which might help you will be there as well, so feel free to browse through the thread first, if you can't seem to find what you are looking for, just tell us, and we will answer your question directly...

oh i figured it out. haha sorry

but i am confused about the part two (or the second page)

what do they mean by "define Tn(a,x) as the sum of the first n terms, for various values of a and x"?

do i just have to list a bunch of versions of the example,using different values?

so i could say "T2(1,2) is the sum of the first two terms when a=1 and x=2"

i just dont get the whole "define" term. what are they implying?

thanks in advance for helping out! XD

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oh i figured it out. haha sorry

but i am confused about the part two (or the second page)

what do they mean by "define Tn(a,x) as the sum of the first n terms, for various values of a and x"?

do i just have to list a bunch of versions of the example,using different values?

so i could say "T2(1,2) is the sum of the first two terms when a=1 and x=2"

i just dont get the whole "define" term. what are they implying?

thanks in advance for helping out! :)

so i could say "T2(1,2) is the sum of the first two terms when a=1 and x=2"

-you just answered your question XD

Since basically it is tryna tell you whilst showing you with the given example (2,5)? Something like that. So yeah.

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so i could say "T2(1,2) is the sum of the first two terms when a=1 and x=2"

-you just answered your question XD

Since basically it is tryna tell you whilst showing you with the given example (2,5)? Something like that. So yeah.

ahhh i think i am a bit smarter than i give myself credit for haha :)

i panicked a bit earlier, but i feel more confident now

thank you though! for clarifying- it reassured me :)

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ahhh i think i am a bit smarter than i give myself credit for haha :)

i panicked a bit earlier, but i feel more confident now

thank you though! for clarifying- it reassured me :)

Ahaha! That's good news ^^ There is no harm in making sure - It is better to be safe than sorry - :)

ALways a pleasure! XD

Edited by Desy ♫
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  • 1 month later...

Good day everyone!

I am a little stuck at the second part of the portfolio...

It says:

'Let a = 3. Calculate T9(2,x) for various positive values of x.'

How exactly do I do this? Is there any formula I am supposed to use?

any help would be greatly appreciated :)

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Good day everyone!

I am a little stuck at the second part of the portfolio...

It says:

'Let a = 3. Calculate T9(2,x) for various positive values of x.'

How exactly do I do this? Is there any formula I am supposed to use?

any help would be greatly appreciated :)

Use your calculator. Like when a=3 and x=1, when a=3 and x=2, when a=3 and x=3, etc etc... Calculate them like you did in the previous part. Calculate each value one by one.

The 'formula' that you're asking for is the general statement that you actually need to find :P

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Use your calculator. Like when a=3 and x=1, when a=3 and x=2, when a=3 and x=3, etc etc... Calculate them like you did in the previous part. Calculate each value one by one.

The 'formula' that you're asking for is the general statement that you actually need to find :P

Hi Desy :)

Ok if I understood this question correctly I have to find the sum for the first nine terms for a=2 x= 1 and a=2 x=2 and a=2 x=3........

You said: 'calculate them like you did in the previous part.' This is very helpfull! :). But I thought that as the question does not say 'using technology' there must be some other way not involving excel or a calculator...

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When the portfolio tells us to "Define Tn (a,x)" we simply define it and do nothing more, correct?

note: I have Pro-D day tomorrow, so I have no way to contact my teacher.

Secondly when I use my observations from the "investigations" to find teh general statement of the infinite sum,

do I simply state it or must I provide work on how I achieved the general statement or general solution of "Sn=x^a"?

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