Function Display As Is

Hi all,

I wish to display a transfer function in the form that is shown below.

I am having trouble with the 5*(s+15) term, as MATLAB is by default distributing the 5 into the function and displaying 5*(s+75).

I wrote a MATLAB function which prompts the user for input polynomials and displays the output as the ratio of factors and as the ratio of polynomials once the factors are expanded.

function [factors,polynomials] = test(numpoly,denpoly)
%UNTITLED Summary of this function goes here
%   Detailed explanation goes here
syms s
numpoly = input('Please enter numerator polynomial as a function of s: ')
denpoly = input('Please enter denominator polynomial as a function of s: ')
factors = (numpoly/denpoly)
polynomials = expand(numpoly)/expand(denpoly)

pretty(factors)
pretty(polynomials)


end

%And the Outputs:
%    (5 s + 75) (s + 26) (s + 72)
%    ----------------------------
%               2   2
%     s (s + 56)  (s  + 5 s + 30)
%
%            3        2
%         5 s  + 565 s  + 16710 s + 140400
%    ------------------------------------------
%     5        4         3          2
%    s  + 117 s  + 3726 s  + 19040 s  + 94080 s

[Christopher Chock]

This should help!

https://www.mathworks.com/help/control/ug/transfer-functions.html

Answer 1

[Image Analyst]

Maybe try this:

s = linspace(0.1, 10, 1000);
numerator = 5 * (s + 15) .* (s + 26) .* (s + 72);
denominator = s .* (s + 56).^2 .* (s.^2 + 5 * s + 30);
H = numerator ./ denominator;
plot(s, H, 'b.-');
grid on;
xlabel('s', 'FontSize', 20);
ylabel('H', 'FontSize', 20);

[Marino Kosorcic]

Sorry I must clarify. My task is to display the actual mathematical equation in the two forms: As a ratio of factors and as a ratio of polynomials.

The issue that I am having is in displaying the equation as a ratio of factors. Particularly in displaying 5*(s+15) as it is and not as (5*s+75).