Plotting 3 graphs in the same figure

Write a programme to plot the function f(x)=xsin(pi(9x+1)) over the interval [−1, 1] using increments in x of (a) 0.2, (b) 0.1, and (c) 0.01. The programme should plot the three graphs in the same figure. Include the legend to specify which graph corresponds to which increment. (Observe that the plots for cases (a) and (b) givetotally the wrong picture of ݂f(x)).

Could someone help me?

x = linspace(0.2:0.1:0.01);
y = x*sin(pi*(9*x+1));
y=[-1:1] 
figure
plot(x,y)

[darova]

Can you show your attempts? Where are problems?

[darova]

Yes. I found some mistakes

[Image Analyst]

Anastasia: Did David's solution below work for you? If so, please Accept it.

Answer 1

[David Hill]

z=@(x)x.*sin(pi*(9*x+1));
x={-1:.2:1,-1:.1:1,-1:.01:1};
y=cellfun(@(k)z(k),x,'UniformOutput',false);
plot(x{1},y{1},x{2},y{2},x{3},y{3});