Taking the derivative of a function (looks easy but I don't know how to do it)

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Homework Help Overview

The discussion revolves around the differentiation of the function f(x) = x(x-5)^4, focusing on the application of the product rule and chain rule in calculus.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the use of product and chain rules in differentiation, with attempts to simplify the expression. Questions arise regarding the expansion and factoring of (x-5)^4.

Discussion Status

Participants have provided guidance on factoring rather than expanding the expression. There is an ongoing exploration of how to manipulate the terms to reach a desired form, with no explicit consensus on a single approach yet.

Contextual Notes

Some participants express uncertainty about the necessity of expanding (x-5)^4 and are considering different methods to simplify their results.

appplejack
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Homework Statement


f(x) = x(x-5)^4


Homework Equations





The Attempt at a Solution


I used product rule and chain rule so,
1(x-5)^4 + 4x(x-5)^3(1)

The answer to this question is 5(x-5)^3(x-1). I left it like the answer above. I don't know how to expand (x-5)^4. Thanks.
 
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appplejack said:

Homework Statement


f(x) = x(x-5)^4


Homework Equations





The Attempt at a Solution


I used product rule and chain rule so,
1(x-5)^4 + 4x(x-5)^3(1)

The answer to this question is 5(x-5)^3(x-1). I left it like the answer above. I don't know how to expand (x-5)^4. Thanks.

Your differentiation looks right. Just factorise out the (x-5)^3 and you should be able to get it in that form.
 
appplejack said:

Homework Statement


f(x) = x(x-5)^4


Homework Equations





The Attempt at a Solution


I used product rule and chain rule so,
1(x-5)^4 + 4x(x-5)^3(1)

The answer to this question is 5(x-5)^3(x-1). I left it like the answer above. I don't know how to expand (x-5)^4. Thanks.

Don't expand (x-5)^4. Factor (x-5)^3 out of both terms of your answer and collect what's left.
 
No expansion is necessary, simply rewrite it as (x-5)(x-5)^3. Then you'll have a term x(x-5)^3 and -5(x-5)^3.
 
haha. Why didn't I see that? Thanks guys.
 

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