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Mathematics 24 Online
OpenStudy (iwanttogotostanford):

HELP ASAP

OpenStudy (davejavous):

Firstly, what does it mean if a sequence converges, or diverges?

OpenStudy (iwanttogotostanford):

convergent sequence has a limit — that is, it approaches a real number. A divergent sequence doesn’t have a limit. @davejavous

OpenStudy (iwanttogotostanford):

please help and stay until the end

OpenStudy (iwanttogotostanford):

@DanJS

OpenStudy (davejavous):

I will stay don't worry :)

OpenStudy (iwanttogotostanford):

okgreat if we could go a little faster that'd be great I really just need to get to the correct answer ASAP i have a few other questions to ask you too!:-)

OpenStudy (davejavous):

So you should be able to see that it is a geometric progression? Can you find the common ratio, r?

OpenStudy (iwanttogotostanford):

can you just show me please i need to go soon not trying to be rude but please just show me the whole process that would be most beneficial because i know how i learn best

OpenStudy (iwanttogotostanford):

or someone please

OpenStudy (davejavous):

The sequence is a geometric progression, which means it is in the form: \[ a, ar, ar^2, ar^3 ... \] We know that the first term from the question: \[ a = 108 \] The ratio, r is found by doing: \[ r = \frac{a_{n+1}}{a_n} \]\[ \therefore r = \frac{-18}{108} \]\[ r = -\frac{1}{6}\] Because we multiply by -1/6 each time we know that the following terms will just get smaller and smaller towards 0. This is because of the following limit: \[\lim_{n \rightarrow \infty} x^n = 0 \;\; for \;\;-1 \lt x \lt 1\] Because r is in the range -1<x<1 then it will converge to 0, and 108 x 0 = 0 Hence, the answer is Converges, 0

OpenStudy (iwanttogotostanford):

wow thanks so much! That helped so so much. I will write that down in my noted now. Can you help with another too? your explanations rally help me learn and understand so much that can i have help with another @davejavous

OpenStudy (davejavous):

Yes of course I'll help :D

OpenStudy (iwanttogotostanford):

thank you! Ill start a new post and tag yu.

OpenStudy (davejavous):

@iwanttogotostanford

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