How do I use the chain and product rules together?

  • Thread starter Griffin-Der
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In summary, the conversation discusses a problem with finding the derivative of a product of two functions, one of which is a composite function. It is advised to first use the product rule and then the chain rule to solve the problem. The final output should be x^2 * d/dx[(9 - x^2)^(1/2)] + 2x * (9 - x^2)^(1/2).
  • #1
Griffin-Der
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Ok, I have having a very hard time finding the derivative of this, I have no clue how to do the set up.

x^2(sqrt(9-x^2))

(sorry it's written like that I just have no clue how to type it normally)
So the problem I am having is When do I use the chain rule, and the product rule cohesively, I have the answer to the problem but it does me no good because I cannot solve it.
Thanks in advance.
 
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  • #2
Any help would be greatly appreciated, I have been pulling my hair out for 2 hours :(
 
  • #3
You have a product, so you need to use the product rule first. One of the factors is a composite function, so after you use the product rule, you'll need to use the chain rule.

Don't try to do everything at once.

d/dx[x^2 * (9 - x^2)^(1/2)] = x^2 * d/dx[(9 - x^2)^(1/2)] + 2x * (9 - x^2)^(1/2) = ?
 
  • #4
Thank you so much that cleared it right up for me :)
 

1. What is the chain rule?

The chain rule is a calculus rule that allows us to find the derivative of a composite function (a function that is made up of two or more functions) by breaking it down into simpler parts.

2. What is the product rule?

The product rule is a calculus rule that allows us to find the derivative of a product of two functions by using the derivatives of each individual function.

3. When do I use the chain rule?

The chain rule is used when we have a composite function, meaning a function within another function. It allows us to find the derivative of the outer function while taking into account the derivative of the inner function.

4. What is an example of a chain rule question?

An example of a chain rule question would be finding the derivative of f(x) = sin(x^2). Here, we have a composite function, so we would use the chain rule to find the derivative.

5. Why is the chain rule important?

The chain rule is important because it allows us to find the derivative of more complex functions that cannot be easily solved using basic derivatives. It also has many real-world applications in fields such as physics, engineering, and economics.

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