format long
xu=2;
xl=0.5;
tolerance=0.0001;
err=1;
fxl=xl^3+4*xl^2-10;
fxu=xu^3+4*xu^2-10;
xr=xl-fxl*(xu-xl)/(fxu-fxl);
fxr=xr^3+4*xr^2-10;
while (err > tolerance)
if (fxl*fxr<0)
	%root in lower interval
	%change upper limit
	xu=xr;
	fxu=xu^3+4*xu^2-10;
else
	%root in upper interval
	%change lower limit
	xl=xr;
	fxl=xl^3+4*xl^2-10;
end
oldxr=xr;
xr=xl-fxl*(xu-xl)/(fxu-fxl)
fxr=xr^3+4*xr^2-10;
err=abs((xr-oldxr)/xr)*100;
end
root=xr