trying to understand PDE

[math]

Hi,

I am trying to learn PDE in mathcad,.. Its my first time with PDE, could anyone pls help me with this?

Thanks in advance

[Werner_E]

Its unclear to me what you are trying to do.

q is treated as the spatial variable name first, but when it comes to the BC you treat it like a functon!?

n(q,t) is neither defined nor searched for.

u is first defined as a function in 1 variable and then used as if its a function in two variables.

Concerning the syntax of the Pdesolve() call Alan pointed you in a previous thread to the appropriate help page. Please read and use the information given there and study the examples and the quicksheet.

[math]

this became a bit confusive, when i used u many times.

well this is what i want to define actually du/dt (q,t) = -n (q,t)*v (q,t)

what do u mean by BC?

[Werner_E]

preeti baskaran wrote:

this became a bit confusive, when i used u many times.

well this is what i want to define actually du/dt (q,t) = -n (q,t)*v (q,t)

And what do you know about n and v? You are just searching for u?

what do u mean by BC?

Boundary condition.

[math]

And what do you know about n and v? You are just searching for u?

n and v are just two varibles which are initiliased and they should act according to two contraints that is q = quality and t = time.

[Werner_E]

preeti baskaran wrote:

And what do you know about n and v? You are just searching for u?

n and v are just two varibles which are initiliased and they should act according to two contraints that is q = quality and t = time.

So n and v are NOT variables but (undefined) functions!?

Looks to me like you are trying to solve a *system* of equations, aren't you?

[math]

So n and v are NOT variables but (undefined) functions!?

ok, now I am confused between the terms.

it can be interpreted as the the rate of change of -n and q with respect to q and t. defining them as functions is to set the initial contions in mathcad, isnt it?

[Werner_E]

preeti baskaran wrote:

So n and v are NOT variables but (undefined) functions!?

ok, now I am confused between the terms.

it can be interpreted as the the rate of change of -n and q with respect to q and t. defining them as functions is to set the initial contions in mathcad, isnt it?

No, but if n and v should change dependent on q and t, they are functions in those two variables.

[HarveyHensley]

It looks to me like you have an ode system, not a pde. Look at odesolve.

[AlanStevens]

The attached file contains some comments and questions aimed at pointing you in the right direction (I hope!).

Alan

[math]

thanks! I will look on it