function bisection(myf,left,right,Tol);
N=floor(log((right-left)/Tol)/log(2));
Count=1;
a=left;
b=right;
RootFound=false;
disp([a b]);
while ((RootFound==false) && (Count<=N))
    m=a+(b-a)/2;
    if(feval(myf,m)==0)
        RootFound=true;
        r=m;
    else
       if(sign(feval(myf,m))==sign(feval(myf,a)))
          a=m;
       else
          b=m;
       end
       r=a+(b-a)/2;
    end
    disp([a b r]);
    Count=Count+1;
end