Partial derivatives with constrained variables

In summary, a partial derivative with constrained variables is a way to find the rate of change of a function while holding other variables constant. They are important in various fields and can be calculated using the chain rule. Some common applications include optimization problems and sensitivity analysis. These derivatives can be negative, indicating a decrease in the function with respect to the constrained variable.
  • #1
jimbo71
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Homework Statement


x^2+y^2=r^2
y-rcos(pheta)
find (partialy/partialr)subscribt phetal, find (partialy/partialpheta)subscribtx, and find (partialy/partial)subsribt pehta


Homework Equations


im not sure how to write this partial in chain rule form. i think the first one (partialy/partialr)subscritpheta would simply be cos(pheta). however i have no idea how to write out the chair rule forumulas for the second and third one. please help




The Attempt at a Solution

 
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  • #2
please help asap !
 

1. What is a partial derivative with constrained variables?

A partial derivative with constrained variables is a mathematical concept used to find the rate of change of a function with respect to one of its variables, while holding all other variables constant. It takes into account any constraints or limitations on the variables, such as an equation or boundary condition.

2. Why are partial derivatives with constrained variables important?

Partial derivatives with constrained variables are important because they allow us to analyze and understand the behavior of multivariable functions in a more precise and controlled way. They are essential in fields such as physics, engineering, and economics where variables are often interdependent and constrained by certain conditions.

3. How do you calculate partial derivatives with constrained variables?

To calculate a partial derivative with constrained variables, you first need to specify the function and the variable you want to differentiate with respect to. Then, use the chain rule to differentiate the function with respect to the constrained variable, while treating the other variables as constants. Finally, substitute any given constraints or conditions into the resulting expression.

4. What are some common applications of partial derivatives with constrained variables?

Partial derivatives with constrained variables are widely used in optimization problems, curve fitting, and sensitivity analysis. They are also essential in fields such as thermodynamics, where constraints such as energy conservation laws play a crucial role in understanding the behavior of a system.

5. Can partial derivatives with constrained variables be negative?

Yes, partial derivatives with constrained variables can be negative. This indicates that the function is decreasing with respect to the constrained variable. It is important to consider the sign of the partial derivative when interpreting its meaning in a particular context.

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