Solve cubic equation in MATLAB
3 views (last 30 days)
Show older comments
I need to solve a cubic equation but I don't know how to do it. Here is my coding:
B=80.73233784;
xc=152.01;
R=82.05746;
for i=1:0.1:200
x(i)=-50+i;
y(i)=(10^(7.23086-(1175.581/(x(i)+271.079))))*0.001315789473684;
a(i)=y(i)/(R*x(i));
b(i)=(4.9343*((xc/x(i))^1.5)*B)-B-((y(i)/(R*x(i)))*(B^2));
c(i)=4.9343*((xc/x(i))^1.5)*(B^2);
m=[a -1 b -c];
r=roots(m);
end
This is my equation to be solved for "v": ((a(i)*(v^3))-(v^2)+(b(i)*v)-c(i))=0;
Here "a", "b" and "c" changes with respect to "x" and "y". I want to eliminate the negative and complex roots but I am unable to do so. Moreover program shows error that roots can't be found. I am new to MATLAB and don't know much about its functions. Kindly help me. Thank you.
0 Comments
Accepted Answer
Rick Rosson
on 24 Mar 2012
>> doc roots
>> doc isreal
2 Comments
Rick Rosson
on 25 Mar 2012
Those are commands that you can type at the MATLAB command line. Please try it.
More Answers (0)
See Also
Products
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!