Given the sum of the series, Find the value of d.

Please Help. Will give medal and fan :-)

Question

Given the sum of the series, Find the value of d. 

Please Help. Will give medal and fan :-)

anonymous · Answer

$$3+\frac{1}{4}(3+d)+\frac{1}{4^2}(3+2d)+....\infty = 8$$

anonymous · Answer

@ganeshie8 @ParthKohli @experimentX

anonymous · Answer

@e.mccormick @eliassaab  @AccessDenied @beccaboo333 @Chamberlain15 @david111 @Evictu_FB @fratlife19

anonymous · Answer

@rational @mathmale

experimentx · Answer

collect 1/4s ... and d/4's

experimentx · Answer

you will need these http://en.wikipedia.org/wiki/Geometric_progression http://en.wikipedia.org/wiki/Arithmetico-geometric_sequence

anonymous · Answer

@experimentX : I do understand that this particular thing deals with AGP ..

experimentx · Answer

just get rid of  'd' by taking common at the moment.

anonymous · Answer

But that's what we're supposed to find! 'd'!

anonymous · Answer

@ganeshie8 @Hero @hartnn @dumbcow @Nurali @nincompoop @eliassaab @AustinC @CO_oLBoY @ranga @tyr1 @UH60blackhawk @Valestrum @xTribalKing93x @zzr0ck3r

dumbcow · Answer

http://en.wikipedia.org/wiki/Arithmetico-geometric_sequence#Sum_to_infinite_terms a = 3 r = 1/4

shiraz14 · Answer

@newtoos: @dumbcow is correct. Please use the formula provided for S(inf) of the AGP as follows:
$$S_{\infty} = \frac{ a }{ 1-r } + \frac{ rd }{ (1-r)^{2} }$$, where S(inf)=8, a=3 & r=1/4.

anonymous · Answer

Shoot. I knew that formula. i know how to use it. I knew the a. But the whole time i took r as 4 not 1/4 :'(