How to plot polynomial in matlab

equation is f(x) = 150x - 400x^2 + 500x^3

Want to plot f(x) for x= 0 to 0.8

need to have a legend

[Dyuman Joshi]

This seems like a homework assignment. Show us what you have tried yet.

[Sam Chak]

Hi @Madison,

First things first, make sure to bookmark the Help Center, and then search for the keyword 'plot'. You will find the relevant information ans examples at this URL: https://www.mathworks.com/help/matlab/ref/plot.html.

It's always a good idea to start by searching in the Help Center before seeking technical assistance, unless the problem is highly specific and no relevant examples can be found in the documentation.

[Madison]

I have tried the following - Getting an error on line 5

epsilon = linspace(0,0.8,100);
sigma = zeros(1,100);
i = 1:length(epsilon);
strain = epsilon(i);
stress = 150*strain - 400*strain^2 + 500*strain^3;
sigma(i) = stress; 

figure;
plot (epsilon, sigma)
xlabel('Strain(ε)');
ylabel('Stress(σ)(kPa)');
title('Stress/Strain for Foam');
grid on;

[Dyuman Joshi]

You need to use element-wise power - power, .^

See - Array vs Matrix Operations

epsilon = linspace(0,0.8,100);

sigma = 150*epsilon - 400*epsilon.^2 + 500*epsilon.^3;

figure;
plot (epsilon, sigma)
xlabel('Strain(ε)');
ylabel('Stress(σ)(kPa)');
title('Stress/Strain for Foam');
grid on;

Answer 1

[Alexander]

Some homework assistance and solution:

x = linspace(0,0.8,1000);
y = 150*x - 400*x.^2 + 500*x.^3;
plot(x,y)

[Dyuman Joshi]

I believe that's solving the problem rather than assisting.

I suggest you edit your answer accordingly.