HELPPP!!! polynomial to transfer function?

Im am having trouble converting from a polynomial to a transfer function automatically. My matlab program computes a denominator for example x^2+2x+1, and a numerator say x^2+3x+2 (x is a symbol). Now i want the program to automatically make a transfer function from these polynomials. I tried collecting the coefficients like eq1=coeffs(x^2+2x+1) and eq2=coeffs(x^2+3x+2) and put these in tf(eq1,eq2) and i get an error. I found that if i copy paste the results like eq1=[1 2 1] and eq2=[1 3 2] i get what i want. I have really big polynomials to deal with and need the program to do it automatically. thanks for the help...

Answer 1

[Teja Muppirala]

Here's an idea.

syms x
eq1 = x^2+2*x+1
eq2 = x^2+3*x+2

s = tf('s')

eq1_s = strrep(char(eq1),'x','s');
eq2_s = strrep(char(eq2),'x','s');

G = eval(eq1_s) / eval(eq2_s)

[Alex]

BOOOOOOOOOMMMMMMMM!!!! wowww i spent like 5 hours on this.

Thanks Teja