Partial Derivatives: Help & Thanks!

In summary, the conversation discusses finding the values of df/dx and df/dy when given certain equations. It is mentioned that df/dx and df/dy can be calculated using different equations and that they both equal 0 due to the given information. The conversation also mentions substituting variables in order to solve the equations.
  • #1
imana41
36
0
please help about this
if f(u,v)=f(y/x,z/x)=0 and z=g(x,y) and
gif.latex?\frac{\partial%20f}{\partial%20v}\neq%200.gif


show
gif.latex?x\frac{\partial%20g}{\partial%20x}+y\frac{\partial%20g}{\partial%20y}=g(x,y).gif


thanks alot
 
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  • #2
imana41 said:
please help about this
if f(u,v)=f(y/x,z/x)=0 and z=g(x,y) and
gif.latex?\frac{\partial%20f}{\partial%20v}\neq%200.gif


show
gif.latex?x\frac{\partial%20g}{\partial%20x}+y\frac{\partial%20g}{\partial%20y}=g(x,y).gif


thanks alot

Can you calculate df/dx and df/dy?
And do you know which value they would take?
 
  • #3
df/dx = df/du . du/dx + df/dv .dv/dx and lik this for df/dy
 
  • #4
imana41 said:
df/dx = df/du . du/dx + df/dv .dv/dx and lik this for df/dy

True.

And since f(y/x, z/x) = 0 it follows that df/dx=0 and that df/dy=0.

So if you write out the equations for df/dx and df/dy you have 2 equations that can be solved.
 
  • #5
20u}{\partial%20y}+\frac{\partial%20f}{\partial%20v}\times%20\frac{\partial%20v}{\partial%20y}=0.gif


but how i linking it to
gif.gif
 
  • #6
imana41 said:
20u}{\partial%20y}+\frac{\partial%20f}{\partial%20v}\times%20\frac{\partial%20v}{\partial%20y}=0.gif


but how i linking it to
gif.gif

You are forgetting to substitute u=y/x and v=g(x,y)/x
 
  • #7
thanks i get the answer
the latest symplify is
\frac{\partial%20g}{\partial%20x}\times%20x-g(x,y)}{x\times%20\frac{\partial%20g}{\partial%20y}}.gif


and then
gif.latex?x\frac{\partial%20g}{\partial%20x}+y\frac{\partial%20g}{\partial%20y}=g(x,y).gif
thanks for your help
and another answer is it true
gif.gif
 
Last edited:

FAQ: Partial Derivatives: Help & Thanks!

What are partial derivatives?

Partial derivatives are a mathematical concept used to calculate the rate of change of a function with respect to one of its variables while holding all other variables constant. In other words, it is a way to measure how much a function changes when only one of its variables is changed.

How are partial derivatives different from regular derivatives?

Regular derivatives calculate the rate of change of a function with respect to one variable, while partial derivatives calculate the rate of change with respect to one variable while holding all others constant. This allows for a more specific analysis of a function's behavior.

When are partial derivatives used?

Partial derivatives are used in various fields such as physics, economics, engineering, and more. They are particularly useful in multivariable calculus for analyzing functions with multiple variables.

How do you find partial derivatives?

To find a partial derivative, you first need to identify the variable you want to differentiate with respect to. Then, treat all other variables as constants and use the standard rules of differentiation. This will give you the partial derivative of the function with respect to the chosen variable.

Why are partial derivatives important?

Partial derivatives are important because they allow us to analyze how a function changes with respect to one variable while holding others constant. This can provide valuable insights into the behavior of a function and is essential in many mathematical and scientific applications.

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