I am trying to solve a symbolic equation of the form
D = lamda^12/339288145381785600000 + lamda^10/18124366740480000 +
lamda^8/7846046208000 + lamda^6/523908000 + lamda^4/25200
where lamda
is declared as sym
. The output I get is not in a readable form. Even vpa
is not giving me the answer in readable form. what can be the solution?
First we define the symbolic function:
syms x
f(x) = x^12/339288145381785600000 + x^10/18124366740480000 + ...
x^8/7846046208000 + x^6/523908000 + x^4/25200;
ezplot(f)
Next we find the roots (by solving it numerically). You could also use the vpasolve
MATLAB function:
sol = feval(symengine, 'numeric::solve', f==0, x)
There is 1 real solution and 8 complex ones:
>> sol(:)
sol =
79.624598247213536847657202795915 - 49.037140566365604310129811798328*i
79.624598247213536847657202795915 + 49.037140566365604310129811798328*i
118.88396448746822093664197370373*i
-118.88396448746822093664197370373*i
-111.61305465738189638915837157361*i
111.61305465738189638915837157361*i
0
- 79.624598247213536847657202795915 - 49.037140566365604310129811798328*i
- 79.624598247213536847657202795915 + 49.037140566365604310129811798328*i
Finally we plot the roots:
s = double(sol);
plot(real(s), imag(s), 'r.', 'MarkerSize',25)
axis square; axis([-100 100 -150 150]); box on
line(xlim(), [0 0], 'Color','k', 'LineStyle',':')
line([0 0], ylim(), 'Color','k', 'LineStyle',':')
xlabel('Re(x)'), ylabel('Im(x)'), title('Roots in Complex Plane')
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