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Anousheh1-Visitor
1-Visitor
May 1, 2013
Solved

CUBIC POLYNOMIAL

  • May 1, 2013
  • 1 reply
  • 3441 views

Hello everyone,

This is rather URGENT. Would you please help me to generate a cubic polynomial for the function in the attached worksheet?

Really appreciate your time and help.

Thanks a lot,

Anousheh

Best answer by Werner_E

Didn't we had that same kind of question sometimes before? Same methods apply, see attached

1 reply

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Werner_E25-Diamond IAnswer
25-Diamond I
May 2, 2013

Didn't we had that same kind of question sometimes before? Same methods apply, see attached

A
Anousheh1-VisitorAuthor
1-Visitor
May 2, 2013

Hello Werner,

Sorry, I had a wrong sign in the equation. Please see the correct worksheet attached.

Thank you so much. You are right. We had this before, I had problem with defining i !!!

1- How do you decide the range for i?

2- And also, how do you define alpha sub i?

3- Why the graph does not plot Chi(alpha) at the bottom of the worksheet? Please see the attached.

4- How can we refine the polynomial to get 1 for Chi at alpha=0.5

Thank you,

Anousheh

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AlanStevens19-Tanzanite
19-Tanzanite
May 2, 2013

Anousheh Rouzbehani wrote:

...

1- How do you decide the range for i?

You decide upper and lower limits. You decide number of points depending on the resolution/closeness of fit you want.

2- And also, how do you define alpha sub i?

Use the [ key i.e. alpha[i produces alpha sub i.

3- Why the graph does not plot Chi(alpha) at the bottom of the worksheet? Please see the attached.

Because you pass a vector of alphas to Chi, and Chi is written in such a way that the product in the numerator returns a scalar when each is a vector. You need to vectorise Chi when you pass it a vector i.e. either put an arrow over the top (see the matrix menu) or pass it individual values, alpha sub i. - see attached.

4- How can we refine the polynomial to get 1 for Chi at alpha=0.5

One (rather coarse) way is simply to weight the point alpha = 0.5 by adding many points with alpha = 0.5 to the vector of points created before you do the fit - see attached.

Alan

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