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    • Thread Starter

    y = lnx

    find in terms of y

    i) log(2)X
    ii) ln (x^2/e)
    where(2) = to the base to

    I'm so confused, what are the log rules/method for these type of questions

    y = ln x = log(e) x

    log(2) x = log(e) x / (log(e) 2) = lnx/ln2 = y/ln2

    ln (x^2/e) = 2ln x - lne = 2y - 1

    the three rules:
    log ab = log a + log b
    log a/b = log a - log b
    log (a^b) = b*log a

    also to change base,

    log(a) b = [log(c) b]/[log(c) a]
    • Thread Starter

    cheers, it was the change of base rule 1 i never learnt.
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Updated: June 18, 2005
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