E90Post
 


Coby Wheel
 
BMW 3-Series (E90 E92) Forum > BIMMERPOST Universal Forums > Off-Topic Discussions Board > Simple Math Equation shortcut help



Reply
 
Thread Tools Search this Thread
      08-06-2009, 07:38 PM   #1
sokdo
Lieutenant
sokdo's Avatar
54
Rep
582
Posts

Drives: 335i E92
Join Date: Jul 2009
Location: Fullerton, CA

iTrader: (0)

Simple Math Equation shortcut help

I remember there was an easy way or a short cut method of figuring this out but I just can't remember, maybe some of you guys can remember back to your high school days?

So solve this equation:

(5/((x+1)^1)+(5/((x+1)^2)+(5/((x+1)^3).....+(5/((x+1)^60) = 50
find X


Wasn't there a shortcut method to solving this really easily? Its like on the tip of my tongue and it's driving me insane lol
Appreciate 0
      08-06-2009, 07:41 PM   #2
MCMLXXXIX
wat
MCMLXXXIX's Avatar
240
Rep
3,406
Posts

Drives: a gr3at whit3 5hark
Join Date: Oct 2008
Location: Oct 2008

iTrader: (0)

OH FUCK!
its also on the tip of my tounge, i have the notes somewhere around here...
__________________

2012 Toyota Highlander SE - PAST - 2008 e92 335i, 2006 e90 325i
Appreciate 0
      08-06-2009, 07:43 PM   #3
Cyber
Second Lieutenant
United_States
96
Rep
285
Posts

Drives: 08
Join Date: Sep 2008
Location: Tri State Area EAST

iTrader: (0)

wtf is ...... ?
Appreciate 0
      08-06-2009, 07:49 PM   #4
sokdo
Lieutenant
sokdo's Avatar
54
Rep
582
Posts

Drives: 335i E92
Join Date: Jul 2009
Location: Fullerton, CA

iTrader: (0)

Quote:
Originally Posted by Cyber View Post
wtf is ...... ?
It means you keep going until you eventually hit to the ^60 so

x^1....+x^6 means
X^1 + x^2 + x^3 + x^4 + x^5 + x^6
Appreciate 0
      08-06-2009, 07:49 PM   #5
jrsbeamer335
Captain
jrsbeamer335's Avatar
United_States
39
Rep
756
Posts

Drives: below 1,500rpm
Join Date: Apr 2007
Location: vegas

iTrader: (5)

lmao i hope this one's a joke
Appreciate 0
      08-06-2009, 07:53 PM   #6
sokdo
Lieutenant
sokdo's Avatar
54
Rep
582
Posts

Drives: 335i E92
Join Date: Jul 2009
Location: Fullerton, CA

iTrader: (0)

Quote:
Originally Posted by jrsbeamer335 View Post
lmao i hope this one's a joke
Nope it sure aint =) By all means please enlighten me if you know how to solve it with the formula and without having to plug those numbers one by one into a calculator
Appreciate 0
      08-06-2009, 08:38 PM   #7
OverDrive
CHEAT TO WIN!!
OverDrive's Avatar
Canada
153
Rep
1,347
Posts

Drives: E92 M3, 718 GT4
Join Date: Oct 2007
Location: Toronto

iTrader: (0)

its a power series. You may want to look into this website:
http://appsci.queensu.ca/courses/APS...ments/nops.pdf

but to simple things out, here's a general equation that you can use c/(1-x)
where c is 5 in this case, and x is 1/(x+1) and something like that.

and that is as far as I remember from my calculus class...lol
________
Portuguese recipes
________
VAPIR NO2
________
fat woman Cams
________
The cigar boss

Last edited by OverDrive; 04-14-2011 at 10:53 PM..
Appreciate 0
      08-06-2009, 08:52 PM   #8
MCMLXXXIX
wat
MCMLXXXIX's Avatar
240
Rep
3,406
Posts

Drives: a gr3at whit3 5hark
Join Date: Oct 2008
Location: Oct 2008

iTrader: (0)

__________________

2012 Toyota Highlander SE - PAST - 2008 e92 335i, 2006 e90 325i
Appreciate 0
      08-06-2009, 09:22 PM   #9
Spaceman Spiff
Captain
93
Rep
847
Posts

Drives: R8, 996 C2, Z4MR (sold)
Join Date: Aug 2007
Location: SF Bay

iTrader: (1)

hehe are u studying for the GMAT?
Appreciate 0
      08-07-2009, 12:35 AM   #10
radix
you know he kills little girls like you
radix's Avatar
No_Country
398
Rep
892
Posts

Drives: -
Join Date: Feb 2008
Location: -

iTrader: (0)

Quote:
Originally Posted by sokdo View Post
I remember there was an easy way or a short cut method of figuring this out but I just can't remember, maybe some of you guys can remember back to your high school days?

So solve this equation:

(5/((x+1)^1)+(5/((x+1)^2)+(5/((x+1)^3).....+(5/((x+1)^60) = 50
find X


Wasn't there a shortcut method to solving this really easily? Its like on the tip of my tongue and it's driving me insane lol
You might be thinking of the fact that in geometric series' (meaning the ratio between elements is constant) of the following type:


1 + 1/(n^1) + 1/(n^2) + 1/(n^3) ... 1/n^N = 1 / ( 1 - ( 1 / n))

i.e.

1 + 1/2 + 1/4 + 1/8 + 1/16 + ... = 1 / (1 - ( 1 / 2 )) = 2




I'm just taking a stab at what you're looking for/remembering. The series you posted terminates, so I'm not sure what you're looking for.
Appreciate 0
      08-07-2009, 01:09 AM   #11
sokdo
Lieutenant
sokdo's Avatar
54
Rep
582
Posts

Drives: 335i E92
Join Date: Jul 2009
Location: Fullerton, CA

iTrader: (0)

Radix you got it haha thanks for all the replies. Actually nah it was something I came up while my friend's younger sis was doing her school work and it just seemed so familiar lol but I don't remember anything from high school too much football
Appreciate 0
      08-07-2009, 01:50 AM   #12
darkphantom
Banned
625
Rep
5,945
Posts

Drives: E93 335i
Join Date: Aug 2007
Location: The place for Bimmers

iTrader: (4)

well there ya go, was going to give you a summation and a formula to figure it out, but I think radix got to it
Appreciate 0
      08-07-2009, 02:00 AM   #13
aut0sh0cker
meh
aut0sh0cker's Avatar
United_States
125
Rep
1,752
Posts

Drives: E92 335i, 997.2 C4S
Join Date: Jan 2008
Location: 91362

iTrader: (2)

what is this? high school math?
Appreciate 0
      08-07-2009, 02:02 AM   #14
Blake
Banned
No_Country
795
Rep
4,647
Posts

Drives: Chevy Aveo
Join Date: May 2008
Location: Parent's Basement

iTrader: (7)

fuck math
Appreciate 0
      08-07-2009, 02:02 AM   #15
darkphantom
Banned
625
Rep
5,945
Posts

Drives: E93 335i
Join Date: Aug 2007
Location: The place for Bimmers

iTrader: (4)

^ says the IT guy who got a closet as his new office

edit: you probably get paid more than math teachers, though.
Appreciate 0
      08-07-2009, 02:06 AM   #16
Blake
Banned
No_Country
795
Rep
4,647
Posts

Drives: Chevy Aveo
Join Date: May 2008
Location: Parent's Basement

iTrader: (7)

Quote:
Originally Posted by darkphantom View Post
edit: you probably get paid more than math teachers, though.
honestly, i'd work outside in this texas heat for what i'm getting paid. closet is great! it's also the coolest room in the building.
Appreciate 0
      08-07-2009, 02:07 AM   #17
darkphantom
Banned
625
Rep
5,945
Posts

Drives: E93 335i
Join Date: Aug 2007
Location: The place for Bimmers

iTrader: (4)

no shit, it's the server room! plus, no one disturbs you but make you walk around every once in a while! don't want to become the caveman now...
Appreciate 0
      08-07-2009, 02:33 AM   #18
Blake
Banned
No_Country
795
Rep
4,647
Posts

Drives: Chevy Aveo
Join Date: May 2008
Location: Parent's Basement

iTrader: (7)

Quote:
Originally Posted by darkphantom View Post
no shit, it's the server room! plus, no one disturbs you but make you walk around every once in a while! don't want to become the caveman now...
i go make a fry's run around noon then proceed to take lunch. i take a lot of cigarette breaks, but i'm doing 5x what the old IT guy did. i've been working late because there are a lot of OE's during business hours, and i'm not a huge fan, but i don't like waking up early anyway.
Appreciate 0
      08-07-2009, 02:34 AM   #19
darkphantom
Banned
625
Rep
5,945
Posts

Drives: E93 335i
Join Date: Aug 2007
Location: The place for Bimmers

iTrader: (4)

oh sorry for the
Appreciate 0
      08-07-2009, 03:17 AM   #20
asian010
Brigadier General
asian010's Avatar
United_States
128
Rep
3,236
Posts

Drives: 335i
Join Date: Feb 2008
Location: bay area

iTrader: (6)

i think its called mathematical induction. you replace the X with 1 then prove it, then replace x with k and prove it, then replace x with k+1 and prove it. if all the proofs work out then there you go.
Appreciate 0
      08-07-2009, 03:20 AM   #21
radix
you know he kills little girls like you
radix's Avatar
No_Country
398
Rep
892
Posts

Drives: -
Join Date: Feb 2008
Location: -

iTrader: (0)

Quote:
Originally Posted by asian010 View Post
i think its called mathematical induction. you replace the X with 1 then prove it, then replace x with k and prove it, then replace x with k+1 and prove it. if all the proofs work out then there you go.
Mathematical induction is used to prove that a mathematical statement is true. What he wanted was a shortcut for the summation of a geometric series.
Appreciate 0
      08-07-2009, 03:28 AM   #22
asian010
Brigadier General
asian010's Avatar
United_States
128
Rep
3,236
Posts

Drives: 335i
Join Date: Feb 2008
Location: bay area

iTrader: (6)

Quote:
Originally Posted by radix View Post
Mathematical induction is used to prove that a mathematical statement is true. What he wanted was a shortcut for the summation of a geometric series.
ahh mybad just looked at the equation agian.

so i pulled out my notes and found this formula under geometric series

1x1-r^n / 1-r
Appreciate 0
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 02:41 PM.




e90post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST