Chain Rule for V=(1/2)*sqrt((v*V)/x)(n*df/dn-f) - Solving for V

In summary, the problem involves finding the velocity profiles in the x and y direction using similarity variables and the equations n=y*sqrt((V)/(v*x)) and Q=sqrt(v*V*x)*f(n). The final answer is V=(1/2)*sqrt((v*V)/x)(n*df/dn-f). The significance of the underscore on v is not clear and the person asking the question is unsure of what they are doing wrong in their solution attempts.
  • #1
juice34

Homework Statement


n=y*sqrt((V)/(v*x) and Q=sqrt(v*V*x)*f(n)
so i have V=-dQ/dx=(dQ/dn)*(dn/dx) and the final answer is V=(1/2)*sqrt((v*V)/x)(n*df/dn-f)

Homework Equations





The Attempt at a Solution


i have tried diff. by hand and also by maple and cannot get the answer. What am i doing wrong, because after all i have to quantities added together and that seems weird to me.
 
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  • #2
What exactly are you trying to do? Your problem statement gives two equations, but doesn't say what you are supposed to do with them or what you are supposed to find.

Also, what's the significance of the underscore on v? You also show it italicized and bolded, which seems like overkill.
 
  • #3
n and Q are my equations that need to be differentiated. And i need to find V(x)=-dQ/dx=(dQ/dn)*(dn/dx), this differential is using similarity variables. For example when i take V(y)=dQ/dy=(dQ/dn)*(dn/dy), i get sqrt(v*x*V)*(df/dn)*sqrt(V/(v*x)), if you would like me to send you the file if you don't understand still, let me know.
This problem deals with a boundary layer of a flat plate, V= velocity(at a distance infinity away from the plate) v(underscore)=kinematic viscosity, and V(x) and V(y) are the velocity profiles in the x and y direction that need to be found.
 

Related to Chain Rule for V=(1/2)*sqrt((v*V)/x)(n*df/dn-f) - Solving for V

1. What is the Chain Rule for this equation?

The Chain Rule for this equation is a mathematical rule that allows us to find the derivative of a composite function, where the output of one function becomes the input of another function. It is represented by the formula: (f∘g)'(x) = f'(g(x)) * g'(x).

2. How do you apply the Chain Rule to solve for V in this equation?

To solve for V in this equation, we need to first identify the two functions within the composite function and their respective derivatives. In this case, the functions are the square root function and the division function. We then use the Chain Rule formula to find the derivative of the composite function, which will give us the value of V.

3. Can you provide an example of how to use the Chain Rule to solve for V?

Sure, let's say the equation is V = (1/2)*sqrt((2*V)/x)(3*df/dx-f). We first identify the two functions within the composite function, which are the square root function sqrt() and the division function (2*V)/x. The derivatives of these functions are 1/(2*sqrt()) and -2V/x^2, respectively. We then apply the Chain Rule formula: V' = (1/2)*1/(2*sqrt((2*V)/x)) * (-2V/x^2) = -V/(4x*sqrt((2*V)/x)).

4. Are there any other rules or techniques that can be used to solve for V in this equation?

Yes, there are other techniques such as the Power Rule, Product Rule, and Quotient Rule that can also be used to solve for V in this equation. However, the Chain Rule is the most efficient and straightforward method in this case.

5. Is there a specific order in which the functions should be identified when using the Chain Rule?

Yes, when using the Chain Rule, it is important to identify the functions in the correct order. The inner function should be identified first, followed by the outer function. This will ensure that the derivative is calculated correctly and that the final result is accurate.

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