What is the Derivative of a Cubic Function with a Given Value of x?

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SUMMARY

The discussion centers on finding the derivative of the cubic function y = x³ + 2x at a specific value of x, where dx/dt = 5. To solve for dy/dt when x = 2, the chain rule is applied, specifically using the formula dy/dt = (dy/dx)(dx/dt). The derivative dy/dx is calculated as 3x² + 2, leading to dy/dx = 14 when x = 2. Consequently, dy/dt is determined to be 70.

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Homework Statement



If y = x³ + 2x
and
dx/dt = 5,
find
dy/dt when x = 2.


The Attempt at a Solution



I'm not really sure how to solve this problem at all. It's the first I've seen like this so I don't know what approach I should take.
 
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Use the chain rule in the form:
[tex] \frac{dy}{dt}=\frac{dy}{dx}\frac{dx}{dt}[/tex]
 


Thank you so much!
 

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