>> f=@(x) x*x-4

f =

  function_handle with value:

    @(x)x*x-4

>> [x,history] = HW2bisect(f,0,3,1e-8);
>> format short
>> x

x =

    2.0000

>> format long
>> x

x =

   1.999999998137355

>> history

history =

                   0   3.000000000000000
   1.500000000000000   3.000000000000000
   1.500000000000000   2.250000000000000
   1.875000000000000   2.250000000000000
   1.875000000000000   2.062500000000000
   1.968750000000000   2.062500000000000
   1.968750000000000   2.015625000000000
   1.992187500000000   2.015625000000000
   1.992187500000000   2.003906250000000
   1.998046875000000   2.003906250000000
   1.998046875000000   2.000976562500000
   1.999511718750000   2.000976562500000
   1.999511718750000   2.000244140625000
   1.999877929687500   2.000244140625000
   1.999877929687500   2.000061035156250
   1.999969482421875   2.000061035156250
   1.999969482421875   2.000015258789062
   1.999992370605469   2.000015258789062
   1.999992370605469   2.000003814697266
   1.999998092651367   2.000003814697266
   1.999998092651367   2.000000953674316
   1.999999523162842   2.000000953674316
   1.999999523162842   2.000000238418579
   1.999999880790710   2.000000238418579
   1.999999880790710   2.000000059604645
   1.999999970197678   2.000000059604645
   1.999999970197678   2.000000014901161
   1.999999992549419   2.000000014901161
   1.999999992549419   2.000000003725290

>> history(1,2)

ans =

     3

>> a=history(:,1);
>> b=history(:,2);
>> m=(a+b)/2;
>> plot(m,'r*')
>> k=1:length(m);
>> plot(k,m,'r*')