Results 1 to 6 of 6

Math Help - how to find zeros of ln's

  1. #1
    Newbie
    Joined
    Feb 2009
    Posts
    21

    how to find zeros of ln's

    So my problem is: f(x)= -2+ln(x^2)

    I need to find the zeros of f and to figure out for what real numbers x is f defined. If anyone can explain to me how to do this I would really appreciate it. Thanks in advance!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Banned
    Joined
    Oct 2009
    Posts
    4,261
    Thanks
    2
    Quote Originally Posted by Jasmina8 View Post
    So my problem is: f(x)= -2+ln(x^2)

    I need to find the zeros of f and to figure out for what real numbers x is f defined. If anyone can explain to me how to do this I would really appreciate it. Thanks in advance!
    -2+\ln x^2 = 0 \Longleftrightarrow \ln x^2=2 \Longleftrightarrow x^2=e^2 \Longleftrightarrow |x| =e

    Tonio
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member
    Joined
    Aug 2009
    From
    Israel
    Posts
    976
    f(x) = 0\Rightarrow 2 = ln(x^2) \Rightarrow e^2 = e^{ln(x^2)}

    Can you finish?

    Ah, I see I'm late... never mind!
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Feb 2009
    Posts
    21

    uhh.

    how do you get e^lnx^2 ?? I would really like if you can EXPLAIN to me how to get the answer. Thank you
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Banned
    Joined
    Oct 2009
    Posts
    4,261
    Thanks
    2
    Quote Originally Posted by Jasmina8 View Post
    how do you get e^lnx^2 ?? I would really like if you can EXPLAIN to me how to get the answer. Thank you

    If you deal with these things you should at least know their definition, otherwise it'll be easy to fall into desperation and helplessness:

    \log_a{b}=x \Longleftrightarrow a^x=b

    Now just remember that \ln x=\log_e{x}

    Tonio
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Newbie
    Joined
    Feb 2009
    Posts
    21

    .

    I got it now. Thank you for your help.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. find Zeros
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: July 12th 2010, 01:39 PM
  2. find the zeros of...
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: May 18th 2010, 01:55 PM
  3. Find all the Zeros
    Posted in the Pre-Calculus Forum
    Replies: 9
    Last Post: November 14th 2009, 05:45 PM
  4. Find All Zeros
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: September 22nd 2009, 11:54 AM
  5. Find the zeros
    Posted in the Pre-Calculus Forum
    Replies: 8
    Last Post: September 18th 2009, 05:03 PM

Search Tags


/mathhelpforum @mathhelpforum