function trncal
h1=findobj(0,'tag','trn');
m1=findobj(h1,'tag','EditText1');
nk=get(m1,'string');
n=str2num(nk)
m2=findobj(h1,'tag','EditText2');
rpk=get(m2,'string');
rp=str2num(rpk)
m3=findobj(h1,'tag','EditText3');
rnk=get(m3,'string');
rn=str2num(rnk)
if strcmp(nk,'')|strcmp(rpk,'')|strcmp(rnk,'')
msgbox('you should enter all required data')
else
t=0.5*(((1-rp)/(1+(2*n-1)*rp))+((1-rn)/(1+(2*n-1)*rn)))
msgbox(num2str(t),'trn')
end