c2 geometric series

The QUESTION i need help with is attached.

My calculations said -88 but the answer from the book is -73

please point me in the right direction

question:

my working:

Attachment not found

You only do s7-s2 when using formulas which require the sum from 1 to say n

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Reply 2

bigmansouf

thanks so how do i tackle this question

do i just add the sum from 3 to 7

Reply 3

bigmansouf

bump
any help please?

Reply 4

TeeEm

Original post by bigmansouf

bump
any help please?

this particular question you just add the terms from 3 to 7

No need for formula

thank u

Original post by bigmansouf

thank u

I will make a question like this for one resources where you have to use a formula and i will post the solution here tomorrow night

thanks

Original post by TeeEm

I will make a question like this for one resources where you have to use a formula and i will post the solution here tomorrow night

why u no make step question
that is the only question type there is shortage of

Reply 9

bigmansouf

Original post by Raven of the Sun

why u no make step question
that is the only question type there is shortage of

if you go to his page he started a thread called special papers those are for users to prepare for step papers

plus on his website he is working on sp type papers

Reply 10

bigmansouf

just wait on it drake-meme-generator-teeem-sp-papers-coming-soon-just-wait-on-it-10edb5.jpg

Reply 11

TeeEm

Original post by bigmansouf

thank u

As promised here is a question I made, similar to yours, where the summation formulas are now needed.

Work through the solution carefully

I hope this clears the method

SIGMA MIXED SERIES.pdf100.6KB

Reply 12

bigmansouf

Original post by TeeEm

As promised here is a question I made, similar to yours, where the summation formulas are now needed.

Work through the solution carefully

I hope this clears the method

thank you very much MR T