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# Geometric sequences

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1. (Original post by christinajane)
Ok let me try :-)

first year- 80,000-5000
= 75000

end first = 75000 x 1.04

start of 2nd = 78000 - 5000
= 73000

end of 2nd = 73000 x 1.04
= 75920

=75000 x 1.04^n - 5000 x 1.04 - 5000 x 104
=75000 x 1.04^n - 5000(1.04+1.04^2+1.04^3+1.04^n)

oooo dont laugh if im wildly off track....
You're not wildly off track

Zacken sorry for the tag but do you think I can show her the solution? She's using this as an example for something else?
2. (Original post by Student403)
You're not wildly off track

Zacken sorry for the tag but do you think I can show her the solution? She's using this as an example for something else?
Use your own judgement as to when full solutions are appropriate, I definitely agree with you that they are here.
3. (Original post by Zacken)
Use your own judgement as to when full solutions are appropriate, I definitely agree with you that they are here.
Thank you
4. christinajane

Spoiler:
Show

5. edit: mistake
6. Is that beacuse I am being really stupid??

Sorry I wish my brain worked better at maths...

I think I am gonna kick myself when you give me more clues!!
7. (Original post by christinajane)
Is that beacuse I am being really stupid??

Sorry I wish my brain worked better at maths...

I think I am gonna kick myself when you give me more clues!!
tbh i died while doing that question , i couldn't do it and i'm supposed to be able to do this sorta thing xD
8. (Original post by Student403)
Thank you
Well written as well!
9. (Original post by Zacken)
Well written as well!
Dude xD

That wasn't me
10. (Original post by thefatone)
tbh i died while doing that question , i couldn't do it and i'm supposed to be able to do this sorta thing xD

Thank God! I thought it was just me! I hope these sorta things are not gonna be on the exam!

Ive been dying the last two days trying!!!
11. (Original post by christinajane)
Thank God! I thought it was just me! I hope these sorta things are not gonna be on the exam!

Ive been dying the last two days trying!!!
haha you're not the only one xD
12. (Original post by Student403)
Dude xD

That wasn't me
should have taken the credit.
13. (Original post by Zacken)
should have taken the credit.
Ahh it does look beautiful
14. I get it up to the line

80000 x 1.04^n-1 = 125000 x 1.04 x 1.04^n-1 -125000

Just not sure where that extra 1.04 comes from...

Is this just me not knowing basic manipulation of numbers and equations again?
15. (Original post by christinajane)
I get it up to the line

80000 x 1.04^n-1 = 125000 x 1.04 x 1.04^n-1 -125000

Just not sure where that extra 1.04 comes from...

Is this just me not knowing basic manipulation of numbers and equations again?
From the above line they've just changed

1.04n to 1.041 x 1.04n-1

You know how that works with indices?
16. I thought I did yeah - but not necessarily in this instance....

It just wouldnt come into my head that I could change 1.04^n into 1.04 x 1.04^n-1

Which is partly my problem....

I seem to have lost the basics - been nearly 15 years since I done maths and I only started again last year when I done my GCSE again and thought I done well enough to do my AS level this year....

Plus my teacher isn't very good and never gives homework back - even after complaining I STILL never got it back.....Im practically teaching myself!

He essentially just reads from the text book.
We did four chapters in one lesson the other day!! Two from C2 and two from S1.....I didnt have a clue what he was on about so now I now I need to go through it all more slowly on my own - thereby teaching myself :-/

Anyway - sorry for moaning...its just frustrating

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