Implicit differentiation and chain rule-

In summary, the question is asking for the derivative dr/dq at the point q=1, where R = e^(q+p) and p is defined by the equation q^2*p+p^2*q+qp=3. The given workings attempt to derive the chain for dr/dq but it is unclear if this is the correct approach. Further clarification or guidance is needed in order to solve the problem accurately.
  • #1
SavvyAA3
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The question and my workings are attached:
 
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  • #2
Sorry it seems that attachments do not upload:

Here is the Question:

Suppose R = R(q,p) = e^(q+p), where p = p(q) is defined through the equation

q^2*p+p^2*q+qp = 3

Letn r(q) = R(q,p(q)). Use the chain rule to calculate the derivative dr/dq at the point q=1.



Can you please tell me if it is correct to assume that this question is asking you to insert q^2*p+p^2*q+qp = 3 into e^(q+p), for p?

From there I have tried to derive the chain for dr/dq:

My workings:

since e^(q+q^2*p+p^2*q+qp) = 3, a constant

dr/dq = 0

so the chain
(∂R)/(∂q)*dq/(dq )+(∂R)/(∂r)*dr/(dq)= 0

 (∂R)/(∂r)*dr/(dq)= - (∂R)/(∂q)

 dr/(dq)= - (∂R)/(∂q )* (dr)/(dR)

dr/(dq)= - (∂R)/((∂q )/((∂R)/(∂r)))


I don't think this is the correct chain because I can’t find dr/dqfrom the function given.

I would be most grateful if you could point me along the correct direction for this.
Must I create two chains? i.e. one for dp/dq and then somehow incorporate this for dr/dq?

Thanks.
 

FAQ: Implicit differentiation and chain rule-

What is implicit differentiation?

Implicit differentiation is a method used in calculus to find the derivatives of equations that are not explicitly written in terms of one variable. It involves taking the derivative of both sides of the equation with respect to the variable of interest and using the chain rule to solve for the derivative.

How is implicit differentiation different from explicit differentiation?

Explicit differentiation involves finding the derivative of a function that is explicitly written in terms of one variable, while implicit differentiation involves finding the derivative of a function that is not explicitly written in terms of one variable.

What is the chain rule and how is it used in implicit differentiation?

The chain rule is a rule in calculus that allows us to find the derivative of a composite function. In implicit differentiation, the chain rule is used to find the derivative of the dependent variable with respect to the independent variable.

Can you provide an example of implicit differentiation using the chain rule?

Sure, let's say we have the equation x^2 + y^2 = 25 and we want to find the derivative of y with respect to x. We can rewrite the equation as y = (25-x^2)^1/2. Then, using the chain rule, we get dy/dx = (1/2)(25-x^2)^(-1/2)(-2x). Simplifying, we get dy/dx = -x/(25-x^2)^1/2.

In what real-life situations is implicit differentiation and the chain rule used?

Implicit differentiation and the chain rule are used in many fields of science and engineering, such as physics, chemistry, and economics. One example is in physics, where implicit differentiation is used to find the rate of change of velocity or acceleration in a moving object. In economics, the chain rule is used to find the marginal rate of substitution, which measures the rate at which a consumer is willing to substitute one good for another.

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