Author Topic: Geometric sequences help  (Read 1261 times)

nid404

  • Guest
Geometric sequences help
« on: February 02, 2010, 01:50:33 pm »
 Fatima invests $100 per month for a complete year, with interest added every month at a rate of 1/2% per month at the end of the month. How much would she have to invest at the beginning of the year to have the same total amount after the complete year?


There has to be something in addition to the normal formula for sum of sequences
Please tell me how to solve this

Ans-1167.70

Offline Saladin

  • The Samurai
  • Honorary Member
  • SF V.I.P
  • *****
  • Posts: 6530
  • Reputation: 59719
  • Gender: Male
  • I believe in those who believe in me
    • Student Tech
Re: Geometric sequences help
« Reply #1 on: February 02, 2010, 02:46:33 pm »
The question does not make sense. Like, you want the same amount at the end of the year??? Could you give me the original question please, or the past exam paper from which you got it from.

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: Geometric sequences help
« Reply #2 on: February 02, 2010, 02:47:29 pm »
what do you mean by the same total amount?
if she has A at the start it would be something like A*1.005^12 +100(1-1.005^12)/(1-1.005) =2A but I am not sure if it should be 2A. Can you make the question a bit clearer?

Offline Saladin

  • The Samurai
  • Honorary Member
  • SF V.I.P
  • *****
  • Posts: 6530
  • Reputation: 59719
  • Gender: Male
  • I believe in those who believe in me
    • Student Tech
Re: Geometric sequences help
« Reply #3 on: February 02, 2010, 02:54:12 pm »
thats exactly what I did, and I got 21201, as R.

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: Geometric sequences help
« Reply #4 on: February 02, 2010, 02:59:43 pm »
Do you mean the same total amount again? in which case it should be 2A, but I dont get 1157.7 for A

nid404

  • Guest
Re: Geometric sequences help
« Reply #5 on: February 02, 2010, 03:22:37 pm »
I've put down the question exactly the way it is....word to word
It's from P1 textbook of CIE by Hugh Neil..Ex 14 C Q4......the question is directly from the book...i haven't changed a word....
I don't understand this question myself either....& I need help cuz my mocks r jst a few days away :'(

Offline Saladin

  • The Samurai
  • Honorary Member
  • SF V.I.P
  • *****
  • Posts: 6530
  • Reputation: 59719
  • Gender: Male
  • I believe in those who believe in me
    • Student Tech
Re: Geometric sequences help
« Reply #6 on: February 02, 2010, 03:30:49 pm »
Do your teachers actually do anything productive at school, because mine dont at mine, they finished the whole book on FP1 in 1 day....

It still does not make sense.

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: Geometric sequences help
« Reply #7 on: February 02, 2010, 03:32:42 pm »
Ask them to teach you to dance.

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: Geometric sequences help
« Reply #8 on: February 02, 2010, 03:34:10 pm »
And I think the question has an error.

Offline Saladin

  • The Samurai
  • Honorary Member
  • SF V.I.P
  • *****
  • Posts: 6530
  • Reputation: 59719
  • Gender: Male
  • I believe in those who believe in me
    • Student Tech
Re: Geometric sequences help
« Reply #9 on: February 02, 2010, 03:35:45 pm »
Trust me sir, most of these south asia teachers, they dont even speak in their native tongue or English, but rather something that i call a hideous combination.

But, ususally, the schools that have cambridge AS and A2 are generally good, then again in the context of South asia, sir, I want to request something of you, for once in your lifetime, take a tour of south asia schools, the ones that normal people go to, not the extremely rich, and you will see that ever1 goes for tuition.

I study by myself, and because of that the teachers hate me.
« Last Edit: February 02, 2010, 03:38:59 pm by The Dude 321 »

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: Geometric sequences help
« Reply #10 on: February 02, 2010, 03:43:10 pm »
Ok maybe next year I will tour. Wheredo you suggest? Middle east or pakistan/india/Bangladesh or Malaysia/Singaposre/Indonesia?

nid404

  • Guest
Re: Geometric sequences help
« Reply #11 on: February 02, 2010, 03:45:39 pm »
My math class is 50% philosophy and 10% each of history,geography,spirituality,senseless jokes, 5% concepts of maths and 5% of analysing the beauty of questions and graphs
He hardly ever teaches maths.....He's gone too fast.....we have already begun A2...and hasn't revised a bit of AS for my june examinations.
I shall go to my sir tom and ask him if he could do this....I'm so screwed


@paul sir- Come to India. You r most welcome...You needn't worry abt accomodation ;)...And I will show you my friggin school.....we need teachers like you