function www = functionbstar(xxx, wss, pss, lss, yss ,p_hss, pwss ,y_fss, p_fss ,pw_fss, bss, niss, css, sss, istarss, phib, xi_phiss)
www=[(wss/pss*lss+yss*(p_hss-pwss)+y_fss*(p_fss-pw_fss)-bss*(1-niss)/pss-css)*pss/sss/(1-istarss*(phib/2*(exp(sss*xxx/pss/yss)-1)^2+xi_phiss))-xxx];