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how about a derivative this time?

x^(ax)^(bx)

here's a picture if it's not clear

............(bx)

.....(ax)^

x^

3 Answers

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  • Brenda
    Lv 7
    8 years ago
    Favorite Answer

    Assuming a,b≠0 then:

    y=[x^(ax)]^(bx)

    lny = ln[[x^(ax)]^(bx)]

    lny = bx*ln[x^(ax)]

    lny = bx*ax*lnx

    lny = abx²lnx

    y'/y = 2abx*lnx + ab*x

    y' = y[2abx*lnx +ab*x]

    y' = [x^(ax)]^(bx)*[2abx*lnx +ab*x] =>

    y' = x^(abx²)*x*[2ab*lnx+ab] =>

    y' = ab*x^(abx² +1)*[2lnx +1]

  • Ian
    Lv 6
    8 years ago

    d/dx (x^ax)^bx

    =bx(x^ax)^(bx - 1)(d/dx x^ax)

    =bx(x^ax)^(bx - 1)(ax)(x)^(ax - 1)(1)

    =abx²(x^ax)^(bx - 1)(x)^(ax - 1)

    =abx²{x^[ax^(bx - 1)(ax^1 - 1)]}

    =abx²{x^[ax^(bx - 1 + 1) - 1]}

    =abx²{x^[ax^(bx) - 1]}

    =abx^[ax^(bx) -1 + 2]

    =abx^[ax^(bx) + 1]

    I know this isn't the standard method for solving f(x)^(g(x)) derivatives; it makes use of simpler differentiation methods, for one thing. But I don't see why the answer wouldn't still be correct.

    @ Adrian

    Think you might be incorrect on your interpretation. There's an exponent, ax, with an exponent of its own, bx. Not a single exponent (ax)(bx).

  • 8 years ago

    OK Sparky--

    Wouldn't this be the same as x^(abx^2)??

    let y = x^(abx^2).

    ln (y)= abx^2*ln(x) now take derivatives of both sides and use the product rule

    y'/y = abx^2*(1/x) + ln(x)*2abx

    Now y' = y*[abx +2abx*ln(x)].

    substituting back in for y and factoring out abx you have

    y' = abx*x^(abx^2)*[1+2ln(x)] which can be simplified further to give

    y' = ab*x^(abx^2+1)*[1+2ln(x)]

    Source(s): Math tutor for several years.
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