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

  • Thread starter Thread starter dgamma3
  • Start date Start date
  • Tags Tags
    Odes Separable
dgamma3
Messages
12
Reaction score
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
 
Physics news on Phys.org
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."
 
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:
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.
 
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!
 
Thread 'Direction Fields and Isoclines'
I sketched the isoclines for $$ m=-1,0,1,2 $$. Since both $$ \frac{dy}{dx} $$ and $$ D_{y} \frac{dy}{dx} $$ are continuous on the square region R defined by $$ -4\leq x \leq 4, -4 \leq y \leq 4 $$ the existence and uniqueness theorem guarantees that if we pick a point in the interior that lies on an isocline there will be a unique differentiable function (solution) passing through that point. I understand that a solution exists but I unsure how to actually sketch it. For example, consider a...
Back
Top