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Math Help - logarithmic expressions help

  1. #1
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    logarithmic expressions help

    is this right?

    log(X^2 + 3X + 2) - 2log(X+1)
    =
    log(X+2)(X+1)
    ______________

    log(X+1)^2

    =

    (X+2)
    _________

    (X+1)




    Can you help with these

    ln(ex)

    answer is 1 + LN X according to book, would like to know how to solve.

    and

    ln(xe^x)

    I will probably have more, I have notes and some of my questions have answers in the book(odd ones), but no matter how much I think I know I always get something wrong.
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  2. #2
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    Hi kenny87,

    Quote Originally Posted by kenny87 View Post
    is this right?

    \log(x^2 + 3x + 2) - 2 \log(x+1)=\log \frac{(x+2)(x+1)}{(x+1)^2}=\log \frac{x+2}{x+1}
    Careful not to cancel the log out there in your final step.

    Quote Originally Posted by kenny87 View Post

    Can you help with these

    \ln(ex)<br />
    answer is 1 + \ln x according to book, would like to know how to solve.
    \ln (ex)= \ln e + \ln x = 1 + \ln x

    Remember: \ln e = 1

    Quote Originally Posted by kenny87 View Post

    and

    \ln(xe^x)

    I will probably have more, I have notes and some of my questions have answers in the book(odd ones), but no matter how much I think I know I always get something wrong.
    \ln(xe^x)=\ln x + \ln e^x = \ln x+ x
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  3. #3
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    Careful not to cancel the log out there in your final step.
    you lost me there, did I do something wrong?

    Anyways, thanks for the help.
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  4. #4
    A riddle wrapped in an enigma
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    Quote Originally Posted by kenny87 View Post
    is this right?

    log(X^2 + 3X + 2) - 2log(X+1)
    =
    log(X+2)(X+1)
    ______________

    log(X+1)^2

    =

    (X+2)
    _________

    (X+1)

    After your last = sign, there's no "log". Where did it go?
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  5. #5
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    oops, I knew its just I am not use to typing math problems on a keyboard and forgot.
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  6. #6
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