HOW TO CODE AND PLOT EQUATION

2020 12 7
1 个回答
更新时间：2020 12 7
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I tried to code and plot this Midilli equation but it keep on saying “subscript indices must either be real positive integers or logicals”. I need to plot those decimals but i dont know how
a= 1.1143 k= 0.1791 n= 0.3215 b= 0.00321 t = 11 mins
MR = a•exp(-k(t^n))+b•t

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回答（1 个）

Ameer Hamza
Ameer Hamza 2020-12-7

0 个投票

You are missing multiplication operator between 'k' and t^n.
MR = a*exp(-k*(t^n))+b*t

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korukosheep
korukosheep 2020-12-7
I see... but theres another problem,,, when i tried to put this a = 0.1143 it says “subscript indices must either be real positive integers or logicals”
Walter Roberson
Walter Roberson 2020-12-7
post your current code
korukosheep
korukosheep 2020-12-7
编辑：Walter Roberson 2020-12-7
This is the code i used with the help of Image Analyst
% 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);
But when i tried to change the values of a,b,k,n to decimals it shows “subscript indices must either be real positive integers or logicals”
korukosheep
korukosheep 2020-12-7
I tried to input these values for
a= 1.1143 k= 0.1791 n= 1.3215 b= 0.00321
Walter Roberson
Walter Roberson 2020-12-7
at the command line give the command
clearvars
and then run the code again

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