Matlab code not computing

Question

lateef 2023-7-18

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1997458-matlab-code-not-computing

评论： Image Analyst 2023-7-21

h2m (1).pdf

is anyone able to review my code and tell me why its not outputing correcrtly when i run it im not sure what errors i have

clear
p=-1;
z=-5;
K = 0.05:0.001:100;
a=K;
b=2*K.^2-p*K;
c=-z*K.^2;
root1 = (-b + sqrt(b.^2 - 4.*a.*c))./(2.*a);
root2 = (-b - sqrt(b.^2 - 4.*a.*c))./(2.*a);
root = root1;
K_corresponding = K;
decay_rate = real;
fprintf('The maximal imaginary part is: %f\n', max_imag_part);
fprintf('The corresponding value of K is: %f\n', K_corresponding);
fprintf('The decay rate is: %f\n', decay_rate);
figure
plot(real(root), imag(root));
scatter[real(root(max_index)], imag[root(max_index)], 'red'; 'filled');
Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.
xlabel('Real Part');
ylabel('Imaginary Part');
title('Root Locus Plot');

2 个评论
显示无隐藏无

Stephen23 2023-7-18

编辑：Stephen23 2023-7-18

在 MATLAB Online 中打开

scatter[real(root(max_index)], imag[root(max_index)], 'red'; 'filled');
%                                  ^               ^ should be parentheses 
%                           ^ what is this for?
%      ^ should be parenthesis, not square bracket

lateef 2023-7-18

在 MATLAB Online 中打开

even afiter put in paranthesis my code still computes an error

scatter((real(root(max_index)), imag(root(max_index)), 'red'; 'filled';
Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.
xlabel('Real Part');

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Alan Stevens 2023-7-18

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1997458-matlab-code-not-computing#answer_1275013

在 MATLAB Online 中打开

The use of square brackets in the scatter function is not the only problem! Are you looking for something like this?

p=-1;

z=-5;

K = 0.05:0.001:100;

a=K;

b=2*K.^2-p*K;

c=-z*K.^2;

root1 = (-b + sqrt(b.^2 - 4.*a.*c))./(2.*a);

root2 = (-b - sqrt(b.^2 - 4.*a.*c))./(2.*a);

root = root1;

iroot = imag(root);

maximag = max(iroot);

max_index = find(iroot == maximag);

K_corresponding = K(max_index);

decay_rate = real(root(max_index));

fprintf('The maximal imaginary part is: %f\n',maximag);

The maximal imaginary part is: 1.936492

fprintf('The corresponding value of K is: %f\n', K_corresponding);

The corresponding value of K is: 2.000000

fprintf('The decay rate is: %f\n', decay_rate);

The decay rate is: -2.500000

figure

plot(real(root), imag(root));

hold on

scatter(real(root(max_index)), imag(root(max_index)), 'red', 'filled');

xlabel('Real Part');

ylabel('Imaginary Part');

title('Root Locus Plot');

2 个评论
显示无隐藏无

lateef 2023-7-18

yes thank you for the help

Image Analyst 2023-7-21

If this Answer solves your original question, then could you please click the "Accept this answer" link to award the answerer with "reputation points" for their efforts in helping you? They'd appreciate it. Thanks in advance. 🙂 Note: you can only accept one answer (so pick the best one) but you can click the "Vote" icon for as many Answers as you want. Voting for an answer will also award reputation points.

请先登录，再进行评论。