Derivative Help: differentiate using product rule

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The discussion focuses on differentiating the function (1-2x^3+x^2)((1/x^3)+1) using the product rule. The user has calculated the derivatives of f(x) and g(x) but is encountering difficulties in their application. A correction is noted regarding the derivative of g(x), which should be revised as the current calculation is incorrect. Additionally, there are errors in the application of the product rule for f'(x)g(x). Clarifications on these points are essential for accurately solving the derivative.
digidako
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Homework Statement



(1-2x3+x2)((1/x3)+1)

Homework Equations



f'g(x)+g'f(x)
f'(x)=-6x3+2x
g'(x)=(-1/x4)

The Attempt at a Solution



I found what i believe to be the derivative of both f(x) & g(x) and used the product rule to get to where I am stuck right now:

[(-6x2+2x)(1/x3)]+[(-1/x4)(1-2x3+x2)
 
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digidako said:

Homework Statement



(1-2x3+x2)((1/x3)+1)

Homework Equations



f'g(x)+g'f(x)
f'(x)=-6x3+2x
g'(x)=(-1/x4)

The Attempt at a Solution



I found what i believe to be the derivative of both f(x) & g(x) and used the product rule to get to where I am stuck right now:

[(-6x2+2x)(1/x3)]+[(-1/x4)(1-2x3+x2)
Your result for g'(x) is wrong, assuming that g(x)=1/x3+1. Your f'(x)g(x) is wrong too.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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