x=0:0.1:1
x(3)
x([3 4 6 9])
x([0 1 1 0 0 0 0 1 0 0 1])  % generates error
x(logical([0 1 1 0 0 0 0 1 0 0 1]))
x>(1/3)
x(x>(1/3))

x=0:.001:1;
u0=zeros(size(x));
u0(x<(1/3))=10*sin(33*pi* x(x<(1/3)) );
u0(x>(1/3))=sin(3*pi* x(x>(1/3)) );
plot(x,u0)