Partial derivative using only function notation

In summary, the problem is to find the partial derivative of q(x,y,e(x,y,u)) with respect to x, where e(x,y,u) is a function. The attempt at a solution involved using the chain rule, but the result did not seem correct. The correct solution involves using the sum of partial derivatives, where the variables x,y,u are independent.
  • #1
Bman12345
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Homework Statement


I need to find the partial derivative of the following, with respect to x


q(x,y,e(x,y,u))
where e(x,y,u) is a function


Homework Equations





The Attempt at a Solution


Well, the problem is I don't have a clue how to solve using just the function notation - I'm used to doing it to an actual fuction (if that makes sence)

so I tried doing the chain rule,
(I will use d as I don't know how to get the patial derivative symbol)

[tex]\frac{d q(x,y,e(x,y,u)}{d e(x,y,u)}[/tex] [tex]\times[/tex] [tex]\frac{d e(x,y,u)}{d x}[/tex]

However I do not think this is right. I don't think I use the product rule as it seems to be a function within a function, not two functions times together.

So yeah, what should be an easy problem has me stumped!
 
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  • #2
Use the chain rule, but it should be a sum.

[f(u(x,y,x),v(x,y,x),w(x,y,x))]x=f(1,0,0) ux+f(0,1,0) vx+f(0,0,1) wx=fu ux+fv vx+fw wx

where raised (a,b,c) means differentiate slot 1 a times, slot 2 b times, and slot 3 c times
I assume x,y,u are independent variables.
 
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FAQ: Partial derivative using only function notation

What is a partial derivative?

A partial derivative is a mathematical concept that measures the rate of change of a multivariable function with respect to one of its variables while holding all other variables constant. It is denoted by ∂ (pronounced "partial") and is used to calculate the slope of a tangent line to a curve at a specific point.

How is a partial derivative calculated using only function notation?

To calculate a partial derivative using only function notation, you need to differentiate the function with respect to the desired variable while treating all other variables as constants. For example, if you have a function f(x,y,z), the partial derivative with respect to x would be denoted as ∂f/∂x and calculated by differentiating f(x,y,z) with respect to x.

What is the difference between a partial derivative and a total derivative?

A partial derivative measures the rate of change of a multivariable function with respect to one variable, while holding all other variables constant. On the other hand, a total derivative measures the rate of change of a function with respect to all its variables. In other words, a total derivative takes into account the influence of all variables on the function, while a partial derivative only focuses on one variable.

Why are partial derivatives important in science?

Partial derivatives are important in science because they allow us to analyze and understand the behavior of multivariable functions. They are used in many fields, such as physics, economics, and engineering, to model and predict the behavior of complex systems. They also play a crucial role in optimization problems, where finding the maximum or minimum of a function requires taking partial derivatives.

Can a partial derivative be negative?

Yes, a partial derivative can be negative. This means that the function is decreasing in the direction of the variable with respect to which the partial derivative is taken. In other words, as the value of that variable increases, the output of the function decreases. A positive partial derivative indicates that the function is increasing in that direction, while a partial derivative of zero means that the function is constant in that direction.

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