How can I use vpa() in my MATLAB function to convert a symbolic polynomial into decimal form that displays coefficients in scientific notation (like -2.6228e-06), and where ex

 x = (0:9) * pi / 10;
    y = cos(x);
    polyLagrange(x, y)
    z = pi / 7;
    syms s
    P = polyLagrange(x, y);
    double(subs(P, s, z))

ans =
 
(56195488738499649208603740859375*s^8)/(159723975628756904588584603877376*pi^8) - 

(449563909907079855433250627734375*s^9)/(5750063122635248565189045739585536*pi^9) - 

(57568907601261883291880162078125*s^7)/(547625059298595101446575784722432*pi^7) - 

(232545547737545734655221802959375*s^6)/(182541686432865033815525261574144*pi^6) - 

(103007859212782539731692589374375*s^5)/(4381000474388760811572606277779456*pi^5) + 

(2967793965259438821539819472994625*s^4)/(730166745731460135262101046296576*pi^4) - 

(81756610363852765011123706510025*s^3)/(92001009962163977043024731833368576*pi^3) - 

(2802468829707674447343657251698705*s^2)/(567907468902246771870523036008448*pi^2) - 

(464084660976021733588348031*s)/(182541686432865033815525261574144*pi) + 1
 
    
    

ans =

    0.9010

function i used:

function lag = polyLagrange(x, y)
    syms s
    z = poly2sym([1, 0], s);
    [k, n] = size(x);
    [k, m] = size(y);
    if m ~= n
        disp('Data error')
        return
    end
    v = sym('v', [1, n]);
    w = sym('w', [1, n]);
    for i = 1:n
        v(i) = sym(y(i));
    end
    for k = 1:n-1
        for i = 1:n-k
            w(i) = ((z - x(i)) * v(i + 1) - (z - x(i + k)) * v(i)) / (x(i + k) - x(i));
        end
        for i = 1:n-k
            v(i) = w(i);
        end
    end
    lag=expand ( v ( 1 ) ) ;
   
end

[Torsten]

You must supply the link to "polyLagrange" - it's not a built-in MATLAB function.

[Torsten]

Maybe

format shortE
double(coeffs(polyLagrange(x,y)))

?

[Jakab]

Thank you so much for your time! A big savoiur.