Crazy Partial derivative problem

We can use the given values of u_s(1,0) and v_s(1,0) to find W_s(1,0)In summary, to find W_s(1,0) and W_v(1,0), we must evaluate F_u(u(1,0),v(1,0)) and F_v(u(1,0),v(1,0)) using the given values of u_s(1,0), v_s(1,0), u_t(1,0), and v_t(1,0). These values can then be used to calculate W_s(1,0) and W_v(1,0) using the formula W_s = df/
  • #1
PsychonautQQ
784
10

Homework Statement



Let W = F(u(s,t),v(s,t))

(in my notation, u_s would represent du/ds
u(1,0) = -7
v(1,0) = 3
u_s(1,0)=8
v_s(1,0)=5
u_t(1,0)=-2
v_t(1,0)=-4

F_u(-7,3)=-8
F_v(-7,3)=-2

Find W_s(1,0) and W_v(1,0)

Sort of having a hard time getting started here... I believe
W_s = df/du*du/ds + df/dv*dv/ds
and likewise for W_v...
I don't know how to make the knowledge of F_u(-7,3)=-8 and F_s(-7,3)=-2 useful though.
 
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  • #2
F_u=G(u(s,t),v(s,t))
When (s,t)=(1,0), we must evaluate:
F_u(u(1,0),s(1,0))
 
  • #3
how do I do that with no actual equations X_x?
 
  • #4
You have all the quantities you need calculate W_s.

To get you started
F_u(u(1,0),v(1,0))=F_u(-7,3)=-8
u_s(1,0)=8

so F_u*u_s=-8*8=64

And so on.
 
  • #5
it doesn't matter that the coordinates change from (-7,3) to (1,0)?? I confused X_x
 
  • #6
PsychonautQQ said:
it doesn't matter that the coordinates change from (-7,3) to (1,0)?? I confused X_x
(1,0) are (s,t)-coordinates, whereas (-7,3) are the corresponding (u,v)-coordinates.
 

1. What is a partial derivative?

A partial derivative is a mathematical concept that represents the rate of change of a function with respect to one of its variables, holding all other variables constant. It is a fundamental tool in multivariable calculus and is used to study how a function changes in different directions.

2. Why are partial derivatives important?

Partial derivatives are important because they allow us to analyze how a function changes with respect to each of its variables separately. This is especially useful in fields such as physics and engineering, where many variables are involved in a system and their relationships need to be understood.

3. What makes a partial derivative problem "crazy"?

A partial derivative problem can be considered "crazy" if it involves complex functions, multiple variables, and intricate relationships between them. These types of problems require a deep understanding of the concepts and techniques of partial derivatives, making them challenging and often time-consuming to solve.

4. How can I approach a crazy partial derivative problem?

The key to approaching a crazy partial derivative problem is to break it down into smaller, more manageable parts. Identify the variables involved, their relationships, and any known values or constraints. Then, use the rules of partial derivatives to find the partial derivatives for each variable and combine them to solve the problem.

5. What are some real-world applications of partial derivatives?

Partial derivatives have numerous real-world applications, including in physics, economics, engineering, and statistics. For example, they are used to study the rate of change of temperature in a room, the optimal production levels for a business, the behavior of a chemical reaction, and the risk of a stock portfolio. They are also essential in optimization problems, where the goal is to find the maximum or minimum of a function.

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