How Should Derivatives in Multivariable Chain Rules Be Notated?

In summary, the conversation discusses differentiating a function with respect to its first or second variable and the ambiguity of notation.
  • #1
hojoon yang
9
0
Hi

9785505_1470928696.jpg


I understood above differential

## typo. RHS= 2*f ' (x,2z-x)

but, what is answer of below equation?

5514124_1470928737.jpg


is this right?

f ' ( g(z),2z-x) * g' (z) + f ' ( g(z),2z-x) *2
 
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  • #2
hojoon yang said:
Hi

9785505_1470928696.jpg


I understood above differential

## typo. RHS= 2*f ' (x,2z-x)
This notation is ambiguous, because it is not clear whether you differentiate ##f## w.r.t. the first or second variable. So I would write
$$
\frac{d}{dz} f(x, 2z - x) = 2 D_2f(x, 2z - x)
$$
instead. (There are other notations, but choose one that is clear.)
hojoon yang said:
but, what is answer of below equation?

5514124_1470928737.jpg


is this right?

f ' ( g(z),2z-x) * g' (z) + f ' ( g(z),2z-x) *2
Same comment as above. Change the first ##f'## to ##D_1f## and the second ##f'## to ##D_2f##.
 
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Likes hojoon yang

Related to How Should Derivatives in Multivariable Chain Rules Be Notated?

1. What is multi variable differential?

Multi variable differential is a mathematical concept that deals with the rates of change of multiple variables simultaneously. It involves calculating the partial derivatives of a function with respect to each of the variables.

2. Why is multi variable differential important?

Multi variable differential allows us to understand how a function changes in response to changes in multiple variables, which is crucial in many scientific fields such as physics, engineering, and economics. It also helps us to optimize functions and make predictions based on multiple variables.

3. What is the difference between multi variable differential and single variable differential?

The main difference is that single variable differential only involves calculating the derivative of a function with respect to one variable, while multi variable differential involves calculating the partial derivatives with respect to each of the variables.

4. How is multi variable differential used in real-world applications?

Multi variable differential is used in many real-world applications, such as in modeling physical systems, optimizing processes in engineering, and predicting market trends in economics. It is also used in machine learning and data analysis to understand and predict complex relationships between multiple variables.

5. What are some common techniques for solving multi variable differential equations?

There are various techniques for solving multi variable differential equations, including the chain rule, implicit differentiation, and the method of separation of variables. Other methods such as gradient descent and Newton's method are also commonly used for optimization problems.

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