Chain Rule Q: x[f(x)]^3 + x^2f(x) = 3, f(2) = 1; find f'(2)

grapz

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Jan 13, 2007
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Suppose f is a function such that x[f(x)]^3 + x^2f(x) = 3 and f(2) = 1

find f' (2)

i am not sure how to do this. do i just find the derivative of the first and plug it in?
there is no answer so i'm really stuck.
 
Use the chain rule and product rule. You can sub in your values and solve for f'(2).

\(\displaystyle \L\\x[f(x)]^{3}+x^{2}f(x)=3, \;\ f(2)=1\)

\(\displaystyle \L\\x\underbrace{(3[f(x)]^{2}f'(x))}_{\text{chain rule}}+[f(x)]^{3}+x^{2}f'(x)+f(x)2x\)
 
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