Infinite Geometric Series

[HornetMathRIII]

The sum of an infinite geometric series with first term a and common ratio r < 1 is givenby a/1-r. The sum of a given infinite geometric series is 200, and the common ratio is 0.15. What is the second term of this series?

I am trying to tutor students for the ACT and this question has me stumped. Help please!

 

[JeffM]

The sum of an infinite geometric series with first term a and common ratio r < 1 is givenby a/1-r. The sum of a given infinite geometric series is 200, and the common ratio is 0.15. What is the second term of this series?

I am trying to tutor students for the ACT and this question has me stumped. Help please!

Seriously, you are trying to tutor?

 

[Deleted member 4993]

The sum of an infinite geometric series with first term a and common ratio r < 1 is givenby a/1-r. The sum of a given infinite geometric series is 200, and the common ratio is 0.15. What is the second term of this series?

I am trying to tutor students for the ACT and this question has me stumped. Help please!

The expression for sum(S) is given to you as a function of 'a' (first term of the series) and 'r'(common ratio).

You are given 'S' and 'r' → calculate 'a'

The geometric series is: a + a*r + a*r² + a*r³ + ....

Calculate the second term ......

You need to read the rules of this forum. Please read the post titled "Read before Posting" at the following URL:

http://www.freemathhelp.com/forum/th...217#post322217

We can help - we only help after you have shown your work - or ask a specific question (not a statement like "Don't know any of these")

Please share your work with us indicating exactly where you are stuck - so that we may know where to begin to help you.

 

[HornetMathRIII]

Seriously, you are trying to tutor?

Thanks for the help, support, and encouragement.

 

[HornetMathRIII]

The expression for sum(S) is given to you as a function of 'a' (first term of the series) and 'r'(common ratio).

You are given 'S' and 'r' → calculate 'a'

The geometric series is: a + a*r + a*r² + a*r³ + ....

Calculate the second term ......

You need to read the rules of this forum. Please read the post titled "Read before Posting" at the following URL:

http://www.freemathhelp.com/forum/th...217#post322217

We can help - we only help after you have shown your work - or ask a specific question (not a statement like "Don't know any of these")

Please share your work with us indicating exactly where you are stuck - so that we may know where to begin to help you.

Sorry, I have read it before I was just trying to help someone in a pinch and threw this up here really quick. I appreciate the feedback and apologize for not expanding on what I had tried and failed at.

Thanks again

 

[Deleted member 4993]

Thanks for the help, support, and encouragement.

In stead of being sarcastic - look at what you are really trying to do!

Either you are trying to get us to do the work that you are supposed to do (and get paid for it) - really dishonest

Or you really don't know - and you have no business trying to Tutor ACT (or SAT) students - and you are faking it - really dishonest.

Eitherway - it is unconscionable ...........

 

[HallsofIvy]

Sorry to be so harsh but you are tutoring students in a very important test and you are essentially saying that you cannot do basic reasoning.
You are told that "The sum of an infinite geometric series with first term a and common ratio r < 1 is givenby a/1-r".

You are futher told that "The sum of a given infinite geometric series is 200, and the common ratio is 0.15." So you have a/(1- .15)= 200. Can you solve that for a?

And now that you know both a and r, you can find the second term easily.

 

[JeffM]

Thanks for the help, support, and encouragement.

If you cannot apply basic algebra, you have no business trying to tutor students for a test to demonstrate readiness for college math. I see no reason to support or encourage such an unethical project.