Piecewise Function (Toolbox Doesn't Work)

Hi,

When I try to create a piecewise function with the Symbolic Math Toolbox, it says unrecognized. I cleared the toolbox path cache and reset paths to default. I checked "which ~all <piecewise>" but it's like it doesn't exist.

After creating a piecewise function, I need to plot it discretely. It should look like this:

n2=-2:0.5:0;
f2 = @(n2) (0);
hold on
n=0:0.5:5;
f = @(n) (3*exp(-n).*sin(pi*n));
figure; 
stem(n, f(n));

TIA

[Dyuman Joshi]

Do you have the Symbolic Math Toolbox installed?

Type "ver" in the command window and check the output.

[balla243]

Yes, I installed it and I've confirmed w/ "ver."

Answer 1

[Matt J]

Why bother with symbolic math? Why not just plot as below?

n=linspace(-2,5);
f = @(n) (3*exp(-n).*sin(pi*n)).*(n>=0);

plot(n,f(n),'b',n, 3*exp(-n),':r'); ylim([-3,3])

[balla243]

EDIT: Forgot to delete "n, 20*exp(-n),':r')" when using stem. Can you please explain how the function "starts" at zero? When I check w/ Desmos Graphing Calculator, there should be another x-intercept.

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I appreciate you showing me how to recreate a re-scaled version of the image that I provided. I hoped to use syms to plot as a discrete function and using "stem" gives the error "Incorrect number of inputs for property-value pairs."

n=linspace(-2,5);

f = @(n) (20*exp(-n).*sin(pi*n)).*(n>=0);

stem(n,f(n),'b',n, 20*exp(-n),':r');

[Matt J]

stem only allows you to plot one locus at a time. So, as a stem plot, you could do,

n=linspace(-2,5);
f = @(n) (20*exp(-n).*sin(pi*n)).*(n>=0);

stem(n,f(n),'b');hold on,
plot(n, 20*exp(-n),':r'); hold off
ylim([-20,20])