Plotting Bisection intervals code

Looking for where I plot the intervals on a `plot()` and where ?

function [x,e] = MyBisectFunc(f, a1,b1, number)

format long

c1 = f(a1); d1 = f(b1);

if c1*d1 > 0.0

error ('Func has same sign at both endpoints')

end

for i = 1:number

x = (a1 + b1) /2;

y = f(x);

disp([x,y])

% tried this but nothing showed up on the graph

plot(x,y)

if abs(y) < 10^-8

break

end

if c1*y < 0

b1 = x;

else

a1 = x;

end

end

x = (a1 + b1)/2;

e = (b1 - a1) /2;