How to Approach Proving a Partial Derivative Homework Problem?

In summary, The question is asking about a partial derivative problem and the person is asking for guidance on how to approach it. They have tried one method but are unsure if it is the correct way to solve it. Another user suggests starting from the left hand side and gives a suggestion on how to factor the equation. The original poster admits they are new to partial derivatives and have only briefly covered it in a previous course. They are struggling with the problem and are looking for a simpler method to solve it.
  • #1
xortan
78
1

Homework Statement


I have attached a picture of the problem. The question is the first one.


Homework Equations





The Attempt at a Solution


I tried subbing u and v into the right hand side of the equation. I expanded and simplified but I do not think that is the right way to go about it. If somebody can point me in the right direction that would be very helpful. Thank you!
 

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  • #2
hi xortan! :wink:
xortan said:
I tried subbing u and v into the right hand side of the equation.

my guess is that it's quicker to start from the left hand side

(you could also "factor" it into (∂/∂x + ∂/∂y)(∂/∂x - ∂/∂y)z)

… show us what you get :smile:
 
  • #3
Well I am really new at partial derivative, we just started this course. Was doing a single variable calc course last semester and only touched on this stuff briefly at the end. I am not understanding where to go when starting from the left hand side. I asked another one of my instructors and he showed me this "brute force" way of doing it. I got it to a point of



(∂2z/∂x2 = (∂/∂x)(∂z/∂u)2x + ∂z/∂u * 2 + (∂/∂x)(∂z/∂v)2y

I got to deal with the first term now but the question seems to be blowing up and I know there has to be an easier way of doing this
 

Related to How to Approach Proving a Partial Derivative Homework Problem?

What is a partial derivative?

A partial derivative is a mathematical concept used to measure the rate of change of a function with respect to one of its variables, while holding all other variables constant.

Why is proving a partial derivative important?

Proving a partial derivative is important because it allows us to understand the behavior of a function and how it changes when only one of its variables is varied. This information is crucial in many areas of science and mathematics, such as optimization and physics.

What are the steps for proving a partial derivative?

The steps for proving a partial derivative involve first defining the function and determining which variable is being held constant. Then, we use the limit definition of a derivative to calculate the derivative with respect to the variable of interest. Finally, we simplify the resulting expression and show that it is equal to the partial derivative.

Can a partial derivative be negative?

Yes, a partial derivative can be negative. This means that the function is decreasing with respect to the variable being considered. However, it is important to note that a negative partial derivative does not necessarily mean that the overall function is decreasing, as other variables may be affecting its behavior.

What is the difference between a partial derivative and an ordinary derivative?

The main difference between a partial derivative and an ordinary derivative is that a partial derivative only considers the change in one variable while holding all others constant, whereas an ordinary derivative considers the change in all variables. Additionally, a partial derivative is denoted by ∂ instead of d, and the resulting expression may include other variables that are held constant.

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