function c0401a(form)
{
		if (form.Field2.value == null || form.Field2.value == "0")
		{
			alert("\rVolume cannot be 0\rEnter a non-zero value\rand reCalculate")
		}
		else
		{
			form.result.value = 0 + (form.Field1.value / form.Field2.value) * Math.exp(-form.Field3.value * form.Field4.value)
			form.result.value  = this.roundit(form.result.value,3)
		}
}

function c0401b(form)
{
		  kel = (Math.log(form.Cp1.value)-Math.log(form.Cp2.value))/(form.t2.value - form.t1.value);
		  Cp0 = form.Cp1.value * Math.exp(kel*form.t1.value);
		  V = form.Dose.value/Cp0;
		  t12 = Math.log(2)/kel;
		  cl = kel * V;
//
		  form.kel.value  = this.roundit(kel,3)
		  form.Cp0.value  = this.roundit(Cp0,3)
		  form.V.value    = this.roundit(V,3)
		  form.t12.value = this.roundit(t12,3)
		  form.cl.value = this.roundit(cl,3)
}

function c0401c(form)
{
		if (form.Field2.value == null || form.Field2.value == "0")
		{
		  alert("\rVolume cannot be 0\rEnter a non-zero value\rand reCalculate")
		}
		else
		{
		  result1 = form.Field3.value * Math.exp(form.Field1.value*form.Field4.value);
		  result2 = form.Field2.value * result1;
		  form.result1.value  = this.roundit(result1,3)
		  form.result2.value  = this.roundit(result2,4)
		}
}

function c0401d(form)
{
		kel = (Math.log(form.Cp1.value)-Math.log(form.Cp2.value))/(form.t2.value - form.t1.value);
		Cp0 = form.Cp1.value * Math.exp(kel*form.t1.value);
		V = form.Dose.value/Cp0;
		t12 = Math.log(2)/kel;
		cl = kel * V;

		form.kel.value  = this.roundit(kel,3)
		form.Cp0.value  = this.roundit(Cp0,3)
		form.V.value    = this.roundit(V,3)
		form.t12.value = this.roundit(t12,3)
		form.cl.value = this.roundit(cl,3)


}

function roundit(a,b)
{
	var a;
	var b;
	var c;
	
	c = b - Math.round(0.5 + (Math.log(a)/Math.log(10)));
	c = Math.pow(10,c);
	c = Math.round(c*a)/c;
	return c;
}