plot of y = 2.*(x.^4 - x.^2) isn't right

I set x = linspace(-10, 10); y = 2.*(x.^4 - x.^2); plot(x, y)

and the graph is not correct. what did I do wrong?

[Sam Chak]

Hi @Anna

Which part of the graph is incorrect?

Can you sketch the expected outcome?

[Mahmoud Ashraf]

hi can you write you equation (handwritten)

[DGM]

Seems fine to me.

x = linspace(-10, 10); 
y = 2.*(x.^4 - x.^2); 
plot(x, y)

It might be that you're working in a figure that's already had hold on set, and the axis extents are such that the curve is not visible. If that's the case, either clear the figure (clf) or set the axis limits to something appropriate (use xlim() or ylim())

Answer 1

[Dave B]

I'm pretty sure that's correct, were you expecting to see more of a w-like shape? You might have to zoom in a bit for that (and it helps to add some more points:

tiledlayout(1,2)
nexttile
x = linspace(-10, 10); 
y = 2*(x.^4 - x.^2); 
plot(x, y)
title('default limits')

nexttile
x = linspace(-10, 10, 1000); 
y = 2*(x.^4 - x.^2); 
plot(x, y)
ylim([-1 6])
title('more points, zoomed in')

[Anna]

Yes expecting a w shape. Thanks!