Write a function to find the roots of the cubic equation in matlab without using

Question

Write a function to find the roots of the cubic equation in matlab without using any of the root finding functions in Matlab. Your function statement should be function [ x ] = cubicRoots( a, b, c, d ).

We are supposed to use this link to help https://en.wikipedia.org/wiki/Cubic_function#Roots_of_a_cubic_function but I don't really know what to do. Below is the example of a quadratic equation and what he would want for that:

function [ x ] = quadroots( a, b, c )

% find the real roots of the quadratic equation ax^2 + bx + c

%   input parameters

%       a = real coefficient of cubic equation

%       b = real coefficient of cubic equation

%       c = real coefficient of cubic equation

%   output parameter

%       x = 1 x 2 vector containing the 2 roots of the quadratic equation

D = b^2 - 4*a*c;                       % discriminant

if D >= 0 % real roots

    x(1) = (-b - sqrt(D))/(2*a);

    x(2) = (-b + sqrt(D))/(2*a);

else

    x(1) = NaN;

    x(2) = NaN;

end

end

Explanation / Answer

function [] = solve_cubic() w=10:2:30; a=4*((9*w)-7); b=(-2)*((18*w)-16).*(w+1); c=3*((w+1).^2).*((3*w)-1); d=(-3)*((1+w).^3); f = zeros(1,length(w)); for ii = 1:numel(w) g = roots([a(ii),b(ii),c(ii),d(ii)]); f(ii) = g(g

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

---