clear
format compact
clf

%%
j0 = @(x) besselj(0,x);
fplot(j0, [0 10])
grid on

%%
hold on
plot(fzero(j0, 2), 0, 'or')
plot(fzero(j0, 6), 0, 'or')
plot(fzero(j0, 8), 0, 'or')