Solving Separable ODEs: How to Integrate with Functions of t?

In summary, the conversation is about how to integrate the expression ##\int y^2dy##. The person is also asking for help in understanding how to integrate the expression ##\int \frac{di(t)}{i(t)}dt##, as it is not in the standard form of ##\int \frac{du}{u}##. The expert explains that the two expressions are essentially the same and the only difference is that in the second one, the variable u is explicitly written as a function of t.
  • #1
dgamma3
12
0
I understand how to integrate this: ∫y2dy.

I don't understand how to integrate this:
di(t)/dt = i(t)p(t)
intergrate((di(t)/dt/i(t))*dt = p(t)dt) (see this image: http://i.imgur.com/OdKI309.png)

how do you perform the intergral on the left, seeing as as it not dt, but di(t)?

thanks
 
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  • #2
dgamma3 said:
I understand how to integrate this: ∫y2dy.

I don't understand how to integrate this:
di(t)/dt = i(t)p(t)
intergrate((di(t)/dt/i(t))*dt = p(t)dt) (see this image: http://i.imgur.com/OdKI309.png)

how do you perform the intergral on the left, seeing as as it not dt, but di(t)?

thanks
Can you do this integration? ##\int \frac{du}{u}?##

BTW, there are no such words in English as "intergrate" and "intergral."
 
  • #3
Mark44 said:
Can you do this integration? ##\int \frac{du}{u}?##

BTW, there are no such words in English as "intergrate" and "intergral."

Yes I can do that.

But I do not understand how do integrate (what word do I use?)
∫di(t)/i(t)
 
Last edited:
  • #4
dgamma3 said:
Yes I can do that.

But I do not understand how do integrate (what word do I use?)
∫di(t)/i(t)
This is essentially the same as what I wrote.
##\int \frac{du}{u}## is the same as ##\int \frac{du(t)}{u(t)}##. The only difference is that in the second integral, it is made explicit that u is a function of t.
 
  • #5
Mark44 said:
This is essentially the same as what I wrote.
##\int \frac{du}{u}## is the same as ##\int \frac{du(t)}{u(t)}##. The only difference is that in the second integral, it is made explicit that u is a function of t.
Thank you Mark!
 

1. What is a separable ODE?

A separable ODE, or ordinary differential equation, is a type of differential equation where the dependent variable and independent variable can be separated into separate functions. This allows for the equation to be solved by integrating both sides.

2. Why are separable ODEs important in science?

Separable ODEs are important in science because they can be used to model a wide range of physical phenomena, from population growth to chemical reactions. They also allow for the prediction and understanding of complex systems.

3. How do you solve a separable ODE?

To solve a separable ODE, the equation must first be separated into two functions, one with the dependent variable and the other with the independent variable. Then, both sides are integrated separately, followed by solving for the constant of integration. The result is the general solution to the ODE.

4. What are some real-world applications of separable ODEs?

Some real-world applications of separable ODEs include modeling population growth, radioactive decay, and chemical reactions. They are also used in physics to describe motion and in engineering to analyze electrical circuits.

5. What is the difference between a separable ODE and a non-separable ODE?

The main difference between a separable ODE and a non-separable ODE is that the dependent and independent variables in a separable ODE can be separated into separate functions, while in a non-separable ODE, they cannot. This makes solving a separable ODE much simpler, as it can often be solved by integration. Non-separable ODEs typically require more advanced techniques to solve, such as using series or numerical methods.

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