scilab - Evaluating polynomial at a value of the independent var

[electricpete]

Not a Matlab question but a scilab question.

Let's say I have a polynomial in w.

Something like Residual = 0.0000004 - 7.543D-11w^2 + 2.191D-15w^4
- 1.726D-20w^6 + 5.008D-26w^8 - 6.181D-32w^12 + 3.308D-38w^14 -
6.314D-45w^24 - 1.005D-87w^26


(this arose during Prohl Myklstad calculation of critical speed of a
rotating shaft with 8 shaft elements).


The coefficients have a lot more precision than what is shown in the
output above.


Is there a way to accurately calculate this at a given value of w.
(for example w=10.0)?


Better yet turn it into a function that computes the value of residual
for any given value of w?


I have a suspicion there may be a way to do it by converting to a
string (is there?). If so I am afraid this will lose the precision of
the coefficients.

=====================================
Eng-tips forums: The best place on the web for engineering discussions.

 

[electricpete]

I think the coeff function will do what I need. It returns the coefficients of the polynomial as variables suitable for further calculation.

=====================================
Eng-tips forums: The best place on the web for engineering discussions.