program dichotomie
	double precision a,b,eps,x,y
!	read*, a,b,eps
!	a=0.01
	b=2.
	eps=1.e-10
	n=log((b-a)/eps)/log(2.)
	T=899.
	a=1.e-2
	a1=2.5E-7*T+2.e-4        !2.75e-4
	a3=1.6e-19/1.38e-23/T    !5.3e-13
	a2=4.e-6*T**4*exp(-a3)   !38.65
	S=700.
	do i=1,n
	y=(a+b)/2.
	if(f(a)*f(y).lt.0.) then 
	b=y
	else
	a=y
	endif
c	write(*,10) i,x
c	end do
10    format(i3,3x,f7.5)
	end do
	x=3.26*y
	w=x*y
	Sc=2.29e-3
	Rend=w/S/Sc
c	Resis=x/y
c 	write(*,*)n,x,f(x)
c	print*,a1,a2,a3
	write (*,11)x*1000,y*1000.,w*1000.,Rend*100  !,Resis
11	format(1x,f6.1,4(1x,f7.1))
	end
	function f(y)
	double precision y
	real a1,a2,a3,S
	T=300.
      a1=2.5E-7*T+2.e-4        !2.75e-4
	a3=1.6e-19/1.38e-23/T    !5.3e-13
	a2=4.e-6*T**4*exp(-a3)   !38.65
	S=700.
	f=a1*S - a2*(exp(a3*3.26*y)-1) - y
	return
	end