Need help plotting simple graph in matlab

[Fairy111]

Homework Statement

I need to plot a graph in matlab,
i typed in the following,
V=[0:.2:20];
I=(V^3)-(1.4*V)+0.9;
plot(V,I)

It comes up with the error,
error using mpower, matrix must be square.

Any help into how to fix this problem would be great.

Thankyou

Homework Equations

The Attempt at a Solution

 

[Päällikkö]

A^2 = A*A, i.e. a matrix multiplication. Use A.^2 for element-wise operations:

V=[0:.2:20];
I=(V.^3)-(1.4*V)+0.9;
plot(V,I)

Ought to work.