Hello and welcome to our community! Is this your first visit?
Register
Enjoy an ad free experience by logging in. Not a member yet? Register.
Results 1 to 6 of 6
  1. #1
    Senior Coder
    Join Date
    Aug 2002
    Location
    Kansas City, Kansas
    Posts
    1,518
    Thanks
    0
    Thanked 2 Times in 2 Posts

    Natural Log Question

    I realize that this may not be the appropriate forum for this kind of question, but it was the closest that I could find. Seeing how many of the people around here are very talented mathematicians, I was wondering if someone could solve this for me, and relate to me the steps in which to do so.

    5 ln (2x^3) = 27

  • #2
    jkd
    jkd is offline
    Senior Coder jkd's Avatar
    Join Date
    May 2002
    Location
    metro DC
    Posts
    3,163
    Thanks
    1
    Thanked 18 Times in 18 Posts
    Umm... simple algebra? Is this a homework question?

    5 ln (2x^3) = 27
    ln (2x^3) = 27/5
    2x^3 = e^(27/5)
    x^3 = 0.5 e^(27/5)
    x = (0.5 e^(27/5))^(1/3)

    .......

  • #3
    Rockstar Coder
    Join Date
    Jun 2002
    Location
    USA
    Posts
    9,074
    Thanks
    1
    Thanked 328 Times in 324 Posts
    Yeah but that doesn't come out right.

    If you do that: x = (0.5 e^(27/5))^(1/3)

    Then x=1.73730502

    So then 5*ln(2(1.73730502)^3)=18.6822

    Unless I'm entering the thing in wrong into the windows calculator. I don't have my trusty TI-89 with me here at work.

    It should be more like x=3.025

    -----

    If it is homework, that means your most likely going to be learning the glorious unit circle next or soon after.
    OracleGuy

  • #4
    jkd
    jkd is offline
    Senior Coder jkd's Avatar
    Join Date
    May 2002
    Location
    metro DC
    Posts
    3,163
    Thanks
    1
    Thanked 18 Times in 18 Posts
    I'm right. Try checking again.

    javascript:alert( Math.pow(0.5*Math.exp(27/5), 1/3) )

    x = 4.801608

  • #5
    Senior Coder
    Join Date
    Aug 2002
    Location
    Kansas City, Kansas
    Posts
    1,518
    Thanks
    0
    Thanked 2 Times in 2 Posts
    Thanks JKD. Seeing as I'm only 15, simple algebra to me is a little different than it is to you 2 years of math makes quite a difference, especially when I wasn't paying attention the day we learned about natural logs.

  • #6
    Rockstar Coder
    Join Date
    Jun 2002
    Location
    USA
    Posts
    9,074
    Thanks
    1
    Thanked 328 Times in 324 Posts
    Originally posted by jkd
    I'm right. Try checking again.

    javascript:alert( Math.pow(0.5*Math.exp(27/5), 1/3) )

    x = 4.801608
    Yeah your right... silly google calculator. The windows one doesn't have the e constant.
    OracleGuy


  •  

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •