function[root,ea,iter]=secant(func,delta,xr,es,maxit,varargin)
if nargin<3,error('atleast 3 input arguments required'),end
if nargin<4|isempty(es),es=0.0001;end
if nargin<5|isempty(maxit),maxit=50;end
iter=0;
while (1)
xrold=xr;
xr=xr-((delta*xr*func(xr))/(func(xr+(delta*xr))-func(xr)));
iter=iter+1;
if xr~=0, ea=abs((xr-xrold)/xr)*100;end
if ea<=es|iter>=maxit,break,end
funcxr=func(xr);
end
root=xr;