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This is an archived, read-only copy of the United-TI subforum , including posts and topic from May 2003 to April 2012. If you would like to discuss any of the topics in this forum, you can visit Cemetech's Technology & Calculator Open Topic subforum. Some of these topics may also be directly-linked to active Cemetech topics. If you are a Cemetech member with a linked United-TI account, you can link United-TI topics here with your current Cemetech topics.

Math and Science => Technology & Calculator Open Topic
Author Message
Flofloflo

Member

Joined: 07 Nov 2007
Posts: 120

 Posted: 28 Oct 2009 03:23:09 pm    Post subject: Hello, As the topic title suggests... I was busy with the harmonic series, so I was wondering: If there's a formula where the input of 2^x outputs 0.5 x. What's the formula? Now, my logic was: 2^x results in 0.5 x, x results in Ln(0.5x)/ln(2) = ln(0.5x)/ln(2) - 1. Apparently though, that is not the answer. I am totally unfamiliar with formula's where the input is not simply x... So could somebody help me out with this maybe? Btw, I already discovered that the answer is supposed to be 0.5 * (ln(x)/ln(2)), but I was wondering if there's a fast and logical way to find that? Actually, now that I think about it, maybe the way I found it out eventually was as logical as it gets: First I made a formula for a in 2^a = b, where b is your input, then I did 0.5*a... Okay, sorry I made this thread, I solved my own problem already... -.-Last edited by Guest on 28 Oct 2009 03:35:26 pm; edited 1 time in total
GloryMXE7
Puzzleman 3000

Active Member

Joined: 02 Nov 2008
Posts: 604

 Posted: 28 Oct 2009 03:50:17 pm    Post subject: you can simplify your formula to f(x)=.5ln(x-2) proof ln(x)/ln(2)=ln(x-2)Last edited by Guest on 28 Oct 2009 03:52:55 pm; edited 1 time in total
Weregoose
Authentic INTJ

Super Elite (Last Title)

Joined: 25 Nov 2004
Posts: 3976

 Posted: 28 Oct 2009 03:58:06 pm    Post subject: GloryMXE7 wrote:you can simplify your formula to f(x)=.5ln(x-2) proof ln(x)/ln(2)=ln(x-2)*facepalm* What can I say? Thanks for testing that?Last edited by Guest on 28 Oct 2009 03:58:23 pm; edited 1 time in total
FloppusMaximus