[help] using scilab to plot the direction fiel of ode

[cupcake]

Homework Statement

write down the scilab code that will plot the direction field of dy/dx = x^2 + y^2 -1 on a suitably large rectangle. you have to adjust the interval values of x and y so as to get a clear picture.

Homework Equations

dy/dx = x^2 + y^2 -1

The Attempt at a Solution

I have been trying to do this question, but I'm not sure whether I did it correctly or not, since I have to learn scilab with my own. so, here's my code...

-->deff('[xdot]=f(x,y)', 'xdot=[x(1).^2; y(1).^2-1]')
-->fchamp(f, 1, -4:0.4:4, -4:0.4:4, 1.5)
-->mtlb_axis ( [-4 4 -4 4] )
-->xlabel('x')
-->ylabel('y')

please correct me if I'm wrong..

 

[nate808]

Your code looks correct to me! You have defined the function f(x,y) to be x^2 + y^2 -1 and used the fchamp function to plot the direction field. Adjusting the interval values of x and y is a good idea to get a clear picture. Keep practicing with scilab and you will become more familiar with it. Good luck with your studies!

 

[Architeuthis Dux]

Your code looks correct to me. The deff function creates a function handle for the differential equation, and the fchamp function plots the direction field using this function handle. The mtlb_axis function sets the axes limits, and the xlabel and ylabel functions label the axes. It's important to adjust the interval values for x and y so that the direction field is clear and not too crowded. Keep practicing with scilab and you will become more familiar with it. Good luck!