Find dy/dx, which way should I use?

  • Thread starter Mamdoh Abughalion
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In summary, the conversation discusses finding the derivative of Y^x = X^y using the equations F'( Ln(x)) = 1/x and Lnx^y = yLnx. One person suggests differentiating immediately, while the other expresses concerns about doing so and suggests simplifying the equation first. Ultimately, it is agreed that it does not matter when the differentiation occurs as long as the resulting equation is equivalent to the original one. Additionally, it is noted that when giving a derivative formula, it is important to use the correct notation.
  • #1
Mamdoh Abughalion
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Homework Statement

.[/B]
Find dy/dx
Y^x = X^y

Homework Equations


F'( Ln(x)) = 1/x
Lnx^y = yLnx

The Attempt at a Solution


Ln(Y^x) = Ln(X^y)
X • Lny = Y • Lnx , should I differentiate now or :
Y = X • Lny/Lnx
Y = X • Logxy , then differentiate ?
 
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  • #2
It does not matter when you differentiate as long as the equality you are differentiating is equivalent to the original one.
 
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  • #3
Mamdoh Abughalion said:

Homework Statement

.[/B]
Find dy/dx
Y^x = X^y

Homework Equations


F'( Ln(x)) = 1/x
Lnx^y = yLnx

The Attempt at a Solution


Ln(Y^x) = Ln(X^y)
X • Lny = Y • Lnx , should I derive now or :
Y = X • Lny/Lnx
Y = X • Logxy , then derive?
To find a derivative, you differentiate. The word derive means something else.
 
  • #4
Orodruin said:
It does not matter when you differentiate as long as the equality you are differentiating is equivalent to the original one.
I know that , but my instructer told me that the second way is too much " dangerous " and may lead to wrong solution .
 
  • #5
Also, please don't write ##F'(\ln x) = \frac 1 x##. There is no ##F##. What you mean, and should write, is ##(\ln x)' = \frac 1 x## when you want to give a derivative formula.
 
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1. What is dy/dx and why is it important?

dy/dx, or the derivative of a function, represents the rate of change of that function at a specific point. It is important because it allows us to analyze the behavior of a function and make predictions about its future values.

2. What are the different ways to find dy/dx?

There are several methods for finding dy/dx, including using the power rule, the chain rule, and the product rule. The method you should use depends on the specific function you are working with and the mathematical tools at your disposal.

3. How do I know which method to use to find dy/dx?

The best way to determine which method to use is to first understand the properties of the function you are trying to differentiate. For example, if the function is a polynomial, you can use the power rule. If it is a composite function, you will likely need to use the chain rule.

4. What are some common mistakes to avoid when finding dy/dx?

Some common mistakes to avoid when finding dy/dx include forgetting to apply the chain rule, not simplifying the resulting expression, and miscalculating the derivative of a specific term. It is important to carefully follow the mathematical steps and double-check your work to avoid these errors.

5. Why is it important to check our answer when finding dy/dx?

It is important to check our answer when finding dy/dx to ensure that we have correctly applied the necessary rules and calculations. Additionally, checking our answer allows us to catch any mistakes that may have been made and make corrections, leading to a more accurate and reliable result.

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