Posted by Steff on Saturday, June 11, 2011 at 11:31am.
Should be =4x(3-4x)^3(-12x+3)
This is what I have so far. I am usually pretty good at simplifying but I am missing something here.
f'(x)=2x^2(4)(3-4x)^3(-4) + (3-4x)^4(4x)
Here is where I go wrong. (Answer from book)
f' = 2x^2 (2)(3-4x)(-4) +(3-4x)^2(4x)
= 4x(3-4x)(3-4x) -16x^2(3-4x)
= 4x(3-4x)(3-4x) -4x(3-4x)(4x)
f(x) = 2x^2(9 - 24x +16 x^2)
= 18 x^2 - 48 x^3 +32 x^4
take the derivative of that
= 36 x - 144 x^2 + 128 x^3
= 4x ( 9 - 36 x + 32 x^2)
= 4 x (3-4x)(3-8x)
Unless you have a typo, I have it right and the book has it wrong.
The final answer in the book is
This book has had several errors so far.
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