When I run this function, it generates a graph with only the x-value of -2, why wont it plot the whole vector?

function g

x_min = -2;

x_max = 2;

x = x_min:20:x_max

if x < -pi

g = -1;

elseif x >= -pi && x <= pi

g = cos(x);

else

g = -1;

end

plot(x, g, '--og')

xlabel('Value of x')

ylabel('Value of g(x)')

title('Value of Piecewise function g(x)')

end

Answer 1

[Cris LaPierre]

Because you specified a step size of 20, but min and max of -2 and 2. Since the colon operator stops once the next increment would be greater than the end value, and since -2+20 is >2, you only end up with your start value.

x = -2:20:2

x = -2

[Kyle]

Sorry I am still very new to MatLab, I forgot that it is step size not amount of steps. Thank you.

[Cris LaPierre]

If you want to specify the number of steps, use linspace.

x = linspace(-2,2,20)

x = 1×20

-2.0000 -1.7895 -1.5789 -1.3684 -1.1579 -0.9474 -0.7368 -0.5263 -0.3158 -0.1053 0.1053 0.3158 0.5263 0.7368 0.9474 1.1579 1.3684 1.5789 1.7895 2.0000

You can learn more about creating vectors and arrays in Ch 4 of MATLAB Onramp, a free, self-paced tutorial that covers the basics of MATLAB.