plotting a linear equation

How do I plot a linear equation y=mx+b?

So let's say I have this:

b0= 3 where b0 is the y-intercept b1= 4 where b1 is the x coefficient

Then:

Y= b0-b1*X

How do I plot this?

Answer 1

[per isakson]

Try:

    b0 = 3;
    b1 = 4;
    f = @(x) b0-b1*x;
    ezplot( f, 0, 5 )

[Sergio E. Obando]

Just a note that as of R2016a, ezplot is no longer recommended. If anyone is reading this now, the code would still work or you can update to:

b0 = 3;
b1 = 4;
f = @(x) b0-b1*x;
fplot( f,[0,5])

See fplot for more info.

Answer 2

[Elizabeth]

Or:

By all means, the solution method above will work. However, as your function increases in complexity, that command becomes more and more expensive. Try defining your domain x, then, as a vector:

b0=3; b1=4;
x= linspace(xmin,xmax, n); % Adapt n for resolution of graph
y= b0-b1*x;
plot(x,y)

[Elizabeth]

To plot more than one graph on the same plot use the 'hold on' command.

[Naga Sai]

xmin,xmax,n undefined variables

[Nicholas Copsey]

xmin, xmax, and n are things you can change in the code for various views of the graph

[DGM]

To clarify:

% curve parameters
b0 = 3; % y-intercept
b1 = 4; % (negative) slope

% define x
xmin = 0; % pick these as needed
xmax = 1; 
n = 100; % number of samples
x = linspace(xmin,xmax, n);

% calculate y from x
y = b0 - b1*x;

plot(x,y)

Answer 3

[Ben Le]

b0 = 3;
b1 = 4;

% You can choose any range of x. In this case I chose x is from -50 to +50
x = -50:50;
y = b0 - b1*x;

plot(x,y)

Answer 4

[Andy]

How do I get that into the same graphs? I have points for my data and the equation above is the linear regression. Ezplot gave me two graphs. :(. I want both the points and the linear equation graphed in one figure.

[Elizabeth]

use the 'hold on' command