I DONT KNOW HOW TO CODE AND PLOT THIS EQUATION

i been trying to code and plot this Midilli equation but it's very hard for me and i dont know how to start it

MR= a•exp(-k(t^n))+b•t

where any numbers can be put in a,b,k,n,t

Answer 1

[Image Analyst]

Did you try the plot() function?

% Ask user for four floating point numbers.
defaultValue = {'4', '2', '3', '3'};
titleBar = 'Enter a value';
userPrompt = {'Enter a : ', 'Enter b : ', 'Enter k : ', 'Enter n : '};
caUserInput = inputdlg(userPrompt, titleBar, 1, defaultValue);
if isempty(caUserInput),return,end % Bail out if they clicked Cancel.
% Convert to floating point from string.
a = str2double(caUserInput{1})
b = str2double(caUserInput{2})
k = str2double(caUserInput{3})
n = str2double(caUserInput{4})
t = linspace(0, 3, 1000);
MR = a*exp(-k*(t.^n))+b*t;
% where any numbers can be put in a,b,k,n,t
plot(t, MR, 'b-', 'LineWidth', 2);
grid on;
xlabel('t', 'FontSize', 20);
ylabel('MR', 'FontSize', 20);
title('MR vs. t', 'FontSize', 20);

[korukosheep]

I’ve been trying to put decimals but it keep on saying “subscript induces must either be real positive integers or logicals”

a = 1.1143 K = 0.1791 n = 1.3215 b = 0.00321 t = 11

[Walter Roberson]

notice Image Analyst used

MR = a*exp(-k*(t.^n))+b*t;

for

MR= a•exp(-k(t^n))+b•t

When you converted the dots to * you missed putting in the * between k and the () expression.

[korukosheep]

But this is the problem theres an error when i tried to put decimals

[Walter Roberson]

post your current code

[Image Analyst]

Maybe it's some sort of regional keyboard setting problem. Try changing it. If the decimal point shows up in some other character, maybe you can try input() instead of inputdlg() to enter numbers directly. Otherwise, I've created a version with decimal points in there using the defaults you gave, and also gives you the value for t = 11 exactly.

% Ask user for four floating point numbers.
defaultValue = {'1.1143', '0.00321', '0.1791', '1.3215'}; % a = 1.1143 K = 0.1791 n = 1.3215 b = 0.00321 t = 11
titleBar = 'Enter a value';
userPrompt = {'Enter a : ', 'Enter b : ', 'Enter k : ', 'Enter n : '};
caUserInput = inputdlg(userPrompt, titleBar, 1, defaultValue);
if isempty(caUserInput),return,end % Bail out if they clicked Cancel.
% Convert to floating point from string.
a = str2double(caUserInput{1})
b = str2double(caUserInput{2})
k = str2double(caUserInput{3})
n = str2double(caUserInput{4})
t = linspace(8, 12, 1000);
MR = a*exp(-k*(t.^n))+b*t;
% where any numbers can be put in a,b,k,n,t
plot(t, MR, 'b-', 'LineWidth', 2);
grid on;
xlabel('t', 'FontSize', 20);
ylabel('MR', 'FontSize', 20);
title('MR vs. t', 'FontSize', 20);
% Let's see where it is for t = 11
t11 = 11;
MR11 = a*exp(-k*(t11.^n))+b*t11
xline(t11, 'LineWidth', 2, 'Color', 'r');
yline(MR11, 'LineWidth', 2, 'Color', 'r');
caption = sprintf('MR vs. t.  MR(%.1f) = %f', t11, MR11);
title(caption,  'FontSize', 20);

If it still doesn't work, post your code.