3 Variables Cubic Polynomial

[Anousheh]

HELLO,

Please help me to construct a cubic polynomial with 3 variables.

I am trying to make a cubic polynomial from the function Zf with 3 variables, namely Rho, Alpha andX0

I have attached the worksheet (MathCad 14), so, any help would be greatly appreciated.

Thank you,

Anousheh

[MikeArmstrong]

Why have you created a second thread?

Is this not the same problem as the first?

Mike

[Anousheh]

Hello Mike,

This is the same problem. I had problem creating 3D graph. This is now solved.

I need to write the actual cubic polynomial using the function Zf. No one answered me before, that's why there is another thread.

I need help on this.

Thank you so much

Anousheh

[MikeArmstrong]

Just because someone hasn't replied doesn't mean you won't get a solution.

I have saved your Mathcad worksheet down to M11 format for a wider audience.

Mike

[Anousheh]

Thank you for your time and concern.

I am waiting to get some help.

Anousheh

[RichardJ]

No one answered me before, that's why there is another thread.

That's not a good reason to start another thread. It would be better to post a follow-up in the exiisting thread.

Here's an approach to doing this. It's not really the right way to do functional approximation, but I don't know how to do functional approximation the right way with more than one independent variable!

[Anousheh]

Thank you Richard.

That was a great help.

Now, How do I generate the actual polynomial itself?

[RichardJ]

You really want to look at a 20 term polynomial written out in the long form? OK.

[Anousheh]

Thanks Richard,

This is exactly what I needed. As I am typing, the worksheet is trying to converge (with the yellow light)!

By the way, what is that check box?

Thank you again.

Anousheh

[RichardJ]

It should give you the answer fairly quickly. If it doesn't, there's a problem.

The symbolic calculation will attempt to trace as far back as it can through the calculation of the coefficients. You do not want it to do that. It will probably not even be able to find a solution, and if it can it's not going to be what you want. Passing the coefficients through the checkbox stops the symbolic processor from tracing back down the calculation chain.

[Anousheh]

Hello Richard,

Thank you very much.

It worked.

I appreciate your time and help.

We shall keep in touch.

Thanks again.

Anousheh