Differential equation with three variables

[Nilupa]

Can anyone help me on this equation. I want to find a solution for dr/dt. a, b and c are constants.

 

[chiro]

Hey Nilupa and welcome to the forums.

You need to show us what you have tried, any thoughts you have and any work of any kind you have done on the problem.

Also this is a non-linear partial differential equation of which many don't have known analytic solutions, so this should be kept in mind.

 

[HallsofIvy]

In general, you can't solve a single equation for multiple unknowns. And here you have, even counting a, b, and c as given constants, two unknown functons, r and s, in one equation.

(This is NOT a "partial differential equation"- there is only one independent variable, t.)

 

[chiro]

In general, you can't solve a single equation for multiple unknowns. And here you have, even counting a, b, and c as given constants, two unknown functons, r and s, in one equation.

(This is NOT a "partial differential equation"- there is only one independent variable, t.)

Yes I apologize, I mis-read the graphic wrong: it's not a PDE.

 

[jackmell]

I believe you can solve for $\frac{dr}{dt}$ in that. Note that:

$$\frac{dr}{ds}=\frac{\frac{dr}{dt}}{\frac{ds}{dt}}$$

Ok then, just turn the crank now.

 

[Nilupa]

I believe you can solve for $\frac{dr}{dt}$ in that. Note that:

$$\frac{dr}{ds}=\frac{\frac{dr}{dt}}{\frac{ds}{dt}}$$

Ok then, just turn the crank now.

Thank you so much... Now I think i can solve it.