real procedure tDistr(m,t);value m,t;integer m;real t;
	begin	integer i;
		real x,s,u,v;

		x:=arctan(abs(t)/sqrt(m));v:=cos(x)**2;
		if	m%2*2=m
		then	begin	s:=u:=sin(x)/2; i:=0 	end
		else	begin
				u:=4*arctan(1);s:=x/u;u:=sin(2*x)/u/2;
				if m>=3 then s:=s+u;i:=1
			end; 
		m:=m-2;
	L:	if i>=m then go to out;i:=i+2;u:=u*v*(i-1)/i;s:=s+u;go to L;
	out:	tDistr:= if t<=0 then .5-s else .5+s
	end tDistr;