How do you find the derivative of #y=ln(1-2x)^3#?

1 Answer
Nov 15, 2016

#y' = -6/(1-2x) #

Explanation:

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#y# is composite of two functions #" lnx" " and (1 - 2x)^3 #
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Let #u(x)= lnx " and " v(x) = (1-2x)^3" #
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Then, #" y=u(v(x))" #
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Differentiating this function is determined by applying chain rule.
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#color(red)(y' = u'(v(x))xxu'(x))#
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#color(red)(u'(v(x)) = ?)#
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#u'(x) = 1/x#
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#u'(v(x))) = 1/(v(x))#
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#color(red)(u'(v(x)) = 1/(1-2x)^3)#
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#color(red)(v'(x) = ?)#
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#v'(x) = 3(1-2x)^2(1-2x)'#
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#v'(x) = 3(1-2x)^2(-2)#
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#color(red)(v'(x) = -6(1-2x)^2)#
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#color(red)(y' = u'(v(x))xxu'(x))#
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#y' = 1/(1-2x)^3 xx -6(1-2x)^2 #
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#y' = (-6(1-2x)^2)/(1-2x)^3 #
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#y' = -6/(1-2x) #