Can Implicit Differentiation Reconstruct the Original Equation?

  • Thread starter shreddinglicks
  • Start date
In summary, the conversation discusses a problem involving an underlined equation and a separable equation, and the process of solving the separable equation to work backwards and obtain the underlined equation. It is also mentioned that a negative sign needs to be added to the separable equation, and another tactic must be used to solve the problem.
  • #1
shreddinglicks
212
6

Homework Statement


This is just something I am doing for fun. If you see my attachment you will see I took an equation (underlined) and differentiated it implicitly to give me a separable equation (boxed)

How do I solve the separable equation to work backwards to get the underlined equation?

I apologize in advance, I forgot to bring the negative sign into the separable equation.

Homework Equations


in attachment

The Attempt at a Solution


in attachment
 

Attachments

  • CCI02052017.jpg
    CCI02052017.jpg
    18 KB · Views: 388
Physics news on Phys.org
  • #2
shreddinglicks said:

Homework Statement


This is just something I am doing for fun. If you see my attachment you will see I took an equation (underlined) and differentiated it implicitly to give me a separable equation (boxed)

How do I solve the separable equation to work backwards to get the underlined equation?

I apologize in advance, I forgot to bring the negative sign into the separable equation.

Homework Equations


in attachment

The Attempt at a Solution


in attachment
From your attachment, here's what you have:
##y^2 + 2xy = C##
##2y\frac{dy}{dx} + 2y + 2x\frac{dy}{dx} = 0##
##\frac{dy}{dx} 2x + 2y = -2y##
##\frac{dy}{dx} = \frac{-y}{x + y}## (added the minus sign that you mentioned)

The third line needs parentheses around 2x + 2y.
Your final equation is not separable. Another tactic must be used. One that works is to let u = y/x. That will give you a separable DE.
 

1. What is a separable equation?

A separable equation is a type of differential equation where the variables can be separated into two separate equations that can be solved independently.

2. How do I know if an equation is separable?

An equation is separable if it can be written in the form dy/dx = f(x)g(y), where f(x) and g(y) are functions of x and y, respectively. If an equation can be rewritten in this form, it is separable.

3. What is the general process for solving a separable equation?

The general process for solving a separable equation involves separating the variables, integrating both sides of the equation, and then solving for the constant of integration. This will result in a general solution, which can then be used to find specific solutions by plugging in initial conditions.

4. Are there any specific techniques or methods for solving separable equations?

Yes, there are several techniques that can be used to solve separable equations, such as substitution, integration by parts, and separation of variables. It is important to carefully choose the most appropriate method for each specific equation.

5. Can I use a calculator to solve a separable equation?

Yes, a calculator can be a helpful tool for solving separable equations, especially for evaluating integrals. However, it is important to understand the underlying concepts and steps involved in solving the equation, rather than solely relying on a calculator.

Similar threads

  • Calculus and Beyond Homework Help
Replies
4
Views
1K
  • Calculus and Beyond Homework Help
Replies
2
Views
965
  • Calculus and Beyond Homework Help
Replies
9
Views
1K
  • Calculus and Beyond Homework Help
Replies
10
Views
477
  • Calculus and Beyond Homework Help
Replies
4
Views
1K
  • Calculus and Beyond Homework Help
Replies
7
Views
286
  • Calculus and Beyond Homework Help
Replies
6
Views
3K
  • Calculus and Beyond Homework Help
Replies
2
Views
507
  • Calculus and Beyond Homework Help
Replies
12
Views
1K
  • Calculus and Beyond Homework Help
Replies
1
Views
285
Back
Top