What Is the Correct Partial Derivative of 6xyz?

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Homework Help Overview

The discussion revolves around finding the partial derivative of the expression 6xyz, particularly in the context of a larger equation involving multiple variables. Participants are examining the implications of differentiating with respect to one variable while considering the dependencies of others.

Discussion Character

  • Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Some participants attempt to derive the expression for the partial derivative, expressing confusion over the application of the product rule and the treatment of variables as dependent or independent.
  • Others question the completeness of the problem statement and the notation used, seeking clarification on the correct interpretation of partial derivatives in this context.
  • There is discussion about the correct application of differentiation rules, particularly in relation to the terms involving z and its dependence on x.

Discussion Status

The conversation is ongoing, with participants providing insights and raising questions about the differentiation process. Some have pointed out potential discrepancies in textbook solutions, while others are exploring the implications of variable dependencies. No consensus has been reached yet, but various interpretations and approaches are being discussed.

Contextual Notes

Participants note that the problem involves a relationship defined by an equation, which may affect how derivatives are taken. There is also mention of the need to clarify whether z is treated as a function of x or as an independent variable, which influences the differentiation process.

Calpalned
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Homework Statement


Find (∂z/∂x) of 6xyz

Homework Equations


N/a

The Attempt at a Solution


The correct answer is 6xy(∂z/∂x) but I would like proof of it. I got something different when I tried taking the partial derivative.

6xyz = 6x(yz) = Multiplication rule for derivatives

6(∂x/∂x) + y(∂z/∂x)

What did I do wrong? Thanks
 
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Calpalned said:

Homework Statement


Find (∂z/∂x) of 6xyz
Is this the complete problem statement? Generally speaking you don't find "∂z/∂x" of something, and more than you find "dy/dx" of something. You can, however, find the derivative with respect to, say, x of a function (denoted d/dx(f)) or the partial of some function with respect to, say z (denoted ∂/∂x(f).

The symbols ∂z/∂x and dy/dx represent derivatives, whereas the symbols ∂/∂x and d/dx represent operators that can be applied to functions.

Please verify that what you're providing is the complete problem statement.
Calpalned said:

Homework Equations


N/a

The Attempt at a Solution


The correct answer is 6xy(∂z/∂x) but I would like proof of it. I got something different when I tried taking the partial derivative.

6xyz = 6x(yz) = Multiplication rule for derivatives

6(∂x/∂x) + y(∂z/∂x)

What did I do wrong? Thanks
 
The full question is find (∂z/∂x) of x3 + y3 + z3 + 6xyz = 1
My textbook says the partial derivative is 3x2 + 3z2(∂z/∂x) + 6xy(∂z/∂x) = 0
I don't get how to take the derivative of the red part.
 
Calpalned said:
The full question is find (∂z/∂x) of x3 + y3 + z3 + 6xyz = 1
My textbook says the partial derivative is 3x2 + 3z2(∂z/∂x) + 6xy(∂z/∂x) = 0
I don't get how to take the derivative of the red part.
The derivative above is from my textbook's solutions guide.
 
Calpalned said:
The full question is find (∂z/∂x) of x3 + y3 + z3 + 6xyz = 1
My textbook says the partial derivative is 3x2 + 3z2(∂z/∂x) + 6xy(∂z/∂x) = 0
I don't get how to take the derivative of the red part.
Corrected to: find (∂z/∂x) of if x3 + y3 + z3 + 6xyz = 1

It looks to me like there's a mistake in the solution guide.
##∂/∂x(x^3) = 3x^2## and ##∂/∂x(y^3) = 0## and ##∂/∂x(z^3) = 3z^2 ∂z/∂x##

BUT
##∂/∂x(6xyz) = 6yz## if z is independent of x, in which case ∂z/∂x would be 0. However, if z is dependent on x, you need to use the product rule. Since you're asked to find ∂z/∂x, it must be the case that z is a function of x (is dependent on x).
 

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